Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1 | :mod:`os` --- Miscellaneous operating system interfaces |
| 2 | ======================================================= |
| 3 | |
| 4 | .. module:: os |
| 5 | :synopsis: Miscellaneous operating system interfaces. |
| 6 | |
| 7 | |
Christian Heimes | a62da1d | 2008-01-12 19:39:10 +0000 | [diff] [blame] | 8 | This module provides a portable way of using operating system dependent |
| 9 | functionality. If you just want to read or write a file see :func:`open`, if |
| 10 | you want to manipulate paths, see the :mod:`os.path` module, and if you want to |
| 11 | read all the lines in all the files on the command line see the :mod:`fileinput` |
| 12 | module. For creating temporary files and directories see the :mod:`tempfile` |
| 13 | module, and for high-level file and directory handling see the :mod:`shutil` |
| 14 | module. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 15 | |
Benjamin Peterson | 1baf465 | 2009-12-31 03:11:23 +0000 | [diff] [blame] | 16 | Notes on the availability of these functions: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 17 | |
Benjamin Peterson | 1baf465 | 2009-12-31 03:11:23 +0000 | [diff] [blame] | 18 | * The design of all built-in operating system dependent modules of Python is |
| 19 | such that as long as the same functionality is available, it uses the same |
| 20 | interface; for example, the function ``os.stat(path)`` returns stat |
| 21 | information about *path* in the same format (which happens to have originated |
| 22 | with the POSIX interface). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 23 | |
Benjamin Peterson | 1baf465 | 2009-12-31 03:11:23 +0000 | [diff] [blame] | 24 | * Extensions peculiar to a particular operating system are also available |
| 25 | through the :mod:`os` module, but using them is of course a threat to |
| 26 | portability. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 27 | |
Benjamin Peterson | 1baf465 | 2009-12-31 03:11:23 +0000 | [diff] [blame] | 28 | * All functions accepting path or file names accept both bytes and string |
| 29 | objects, and result in an object of the same type, if a path or file name is |
| 30 | returned. |
Georg Brandl | 76e5538 | 2008-10-08 16:34:57 +0000 | [diff] [blame] | 31 | |
Benjamin Peterson | 1baf465 | 2009-12-31 03:11:23 +0000 | [diff] [blame] | 32 | * An "Availability: Unix" note means that this function is commonly found on |
| 33 | Unix systems. It does not make any claims about its existence on a specific |
| 34 | operating system. |
| 35 | |
| 36 | * If not separately noted, all functions that claim "Availability: Unix" are |
| 37 | supported on Mac OS X, which builds on a Unix core. |
| 38 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 39 | .. Availability notes get their own line and occur at the end of the function |
| 40 | .. documentation. |
| 41 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 42 | .. note:: |
| 43 | |
Christian Heimes | a62da1d | 2008-01-12 19:39:10 +0000 | [diff] [blame] | 44 | All functions in this module raise :exc:`OSError` in the case of invalid or |
| 45 | inaccessible file names and paths, or other arguments that have the correct |
| 46 | type, but are not accepted by the operating system. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 47 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 48 | .. exception:: error |
| 49 | |
Christian Heimes | a62da1d | 2008-01-12 19:39:10 +0000 | [diff] [blame] | 50 | An alias for the built-in :exc:`OSError` exception. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 51 | |
| 52 | |
| 53 | .. data:: name |
| 54 | |
Benjamin Peterson | 1baf465 | 2009-12-31 03:11:23 +0000 | [diff] [blame] | 55 | The name of the operating system dependent module imported. The following |
| 56 | names have currently been registered: ``'posix'``, ``'nt'``, ``'mac'``, |
| 57 | ``'os2'``, ``'ce'``, ``'java'``. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 58 | |
Antoine Pitrou | a83cdaa | 2011-07-09 15:54:23 +0200 | [diff] [blame] | 59 | .. seealso:: |
| 60 | :attr:`sys.platform` has a finer granularity. :func:`os.uname` gives |
| 61 | system-dependent version information. |
| 62 | |
| 63 | The :mod:`platform` module provides detailed checks for the |
| 64 | system's identity. |
| 65 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 66 | |
Martin v. Löwis | 011e842 | 2009-05-05 04:43:17 +0000 | [diff] [blame] | 67 | .. _os-filenames: |
| 68 | |
| 69 | File Names, Command Line Arguments, and Environment Variables |
| 70 | ------------------------------------------------------------- |
| 71 | |
Georg Brandl | 67b21b7 | 2010-08-17 15:07:14 +0000 | [diff] [blame] | 72 | In Python, file names, command line arguments, and environment variables are |
| 73 | represented using the string type. On some systems, decoding these strings to |
| 74 | and from bytes is necessary before passing them to the operating system. Python |
| 75 | uses the file system encoding to perform this conversion (see |
| 76 | :func:`sys.getfilesystemencoding`). |
Martin v. Löwis | 011e842 | 2009-05-05 04:43:17 +0000 | [diff] [blame] | 77 | |
| 78 | .. versionchanged:: 3.1 |
Georg Brandl | 67b21b7 | 2010-08-17 15:07:14 +0000 | [diff] [blame] | 79 | On some systems, conversion using the file system encoding may fail. In this |
| 80 | case, Python uses the ``surrogateescape`` encoding error handler, which means |
| 81 | that undecodable bytes are replaced by a Unicode character U+DCxx on |
| 82 | decoding, and these are again translated to the original byte on encoding. |
Martin v. Löwis | 011e842 | 2009-05-05 04:43:17 +0000 | [diff] [blame] | 83 | |
| 84 | |
Georg Brandl | 67b21b7 | 2010-08-17 15:07:14 +0000 | [diff] [blame] | 85 | The file system encoding must guarantee to successfully decode all bytes |
| 86 | below 128. If the file system encoding fails to provide this guarantee, API |
| 87 | functions may raise UnicodeErrors. |
Martin v. Löwis | 011e842 | 2009-05-05 04:43:17 +0000 | [diff] [blame] | 88 | |
| 89 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 90 | .. _os-procinfo: |
| 91 | |
| 92 | Process Parameters |
| 93 | ------------------ |
| 94 | |
| 95 | These functions and data items provide information and operate on the current |
| 96 | process and user. |
| 97 | |
| 98 | |
| 99 | .. data:: environ |
| 100 | |
| 101 | A mapping object representing the string environment. For example, |
| 102 | ``environ['HOME']`` is the pathname of your home directory (on some platforms), |
| 103 | and is equivalent to ``getenv("HOME")`` in C. |
| 104 | |
| 105 | This mapping is captured the first time the :mod:`os` module is imported, |
| 106 | typically during Python startup as part of processing :file:`site.py`. Changes |
| 107 | to the environment made after this time are not reflected in ``os.environ``, |
| 108 | except for changes made by modifying ``os.environ`` directly. |
| 109 | |
| 110 | If the platform supports the :func:`putenv` function, this mapping may be used |
| 111 | to modify the environment as well as query the environment. :func:`putenv` will |
| 112 | be called automatically when the mapping is modified. |
| 113 | |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 114 | On Unix, keys and values use :func:`sys.getfilesystemencoding` and |
| 115 | ``'surrogateescape'`` error handler. Use :data:`environb` if you would like |
| 116 | to use a different encoding. |
| 117 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 118 | .. note:: |
| 119 | |
| 120 | Calling :func:`putenv` directly does not change ``os.environ``, so it's better |
| 121 | to modify ``os.environ``. |
| 122 | |
| 123 | .. note:: |
| 124 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 125 | On some platforms, including FreeBSD and Mac OS X, setting ``environ`` may |
| 126 | cause memory leaks. Refer to the system documentation for |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 127 | :c:func:`putenv`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 128 | |
| 129 | If :func:`putenv` is not provided, a modified copy of this mapping may be |
| 130 | passed to the appropriate process-creation functions to cause child processes |
| 131 | to use a modified environment. |
| 132 | |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 133 | If the platform supports the :func:`unsetenv` function, you can delete items in |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 134 | this mapping to unset environment variables. :func:`unsetenv` will be called |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 135 | automatically when an item is deleted from ``os.environ``, and when |
| 136 | one of the :meth:`pop` or :meth:`clear` methods is called. |
| 137 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 138 | |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 139 | .. data:: environb |
| 140 | |
| 141 | Bytes version of :data:`environ`: a mapping object representing the |
| 142 | environment as byte strings. :data:`environ` and :data:`environb` are |
| 143 | synchronized (modify :data:`environb` updates :data:`environ`, and vice |
| 144 | versa). |
| 145 | |
Victor Stinner | b745a74 | 2010-05-18 17:17:23 +0000 | [diff] [blame] | 146 | :data:`environb` is only available if :data:`supports_bytes_environ` is |
| 147 | True. |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 148 | |
Benjamin Peterson | 662c74f | 2010-05-06 22:09:03 +0000 | [diff] [blame] | 149 | .. versionadded:: 3.2 |
| 150 | |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 151 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 152 | .. function:: chdir(path) |
| 153 | fchdir(fd) |
| 154 | getcwd() |
| 155 | :noindex: |
| 156 | |
| 157 | These functions are described in :ref:`os-file-dir`. |
| 158 | |
| 159 | |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 160 | .. function:: fsencode(filename) |
Victor Stinner | 449c466 | 2010-05-08 11:10:09 +0000 | [diff] [blame] | 161 | |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 162 | Encode *filename* to the filesystem encoding with ``'surrogateescape'`` |
Victor Stinner | 62165d6 | 2010-10-09 10:34:37 +0000 | [diff] [blame] | 163 | error handler, or ``'strict'`` on Windows; return :class:`bytes` unchanged. |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 164 | |
Antoine Pitrou | a305ca7 | 2010-09-25 22:12:00 +0000 | [diff] [blame] | 165 | :func:`fsdecode` is the reverse function. |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 166 | |
| 167 | .. versionadded:: 3.2 |
| 168 | |
| 169 | |
| 170 | .. function:: fsdecode(filename) |
| 171 | |
| 172 | Decode *filename* from the filesystem encoding with ``'surrogateescape'`` |
Victor Stinner | 62165d6 | 2010-10-09 10:34:37 +0000 | [diff] [blame] | 173 | error handler, or ``'strict'`` on Windows; return :class:`str` unchanged. |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 174 | |
| 175 | :func:`fsencode` is the reverse function. |
Victor Stinner | 449c466 | 2010-05-08 11:10:09 +0000 | [diff] [blame] | 176 | |
| 177 | .. versionadded:: 3.2 |
| 178 | |
| 179 | |
Gregory P. Smith | b6e8c7e | 2010-02-27 07:22:22 +0000 | [diff] [blame] | 180 | .. function:: get_exec_path(env=None) |
| 181 | |
| 182 | Returns the list of directories that will be searched for a named |
| 183 | executable, similar to a shell, when launching a process. |
| 184 | *env*, when specified, should be an environment variable dictionary |
| 185 | to lookup the PATH in. |
| 186 | By default, when *env* is None, :data:`environ` is used. |
| 187 | |
| 188 | .. versionadded:: 3.2 |
| 189 | |
| 190 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 191 | .. function:: ctermid() |
| 192 | |
| 193 | Return the filename corresponding to the controlling terminal of the process. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 194 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 195 | Availability: Unix. |
| 196 | |
| 197 | |
| 198 | .. function:: getegid() |
| 199 | |
| 200 | Return the effective group id of the current process. This corresponds to the |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 201 | "set id" bit on the file being executed in the current process. |
| 202 | |
| 203 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 204 | |
| 205 | |
| 206 | .. function:: geteuid() |
| 207 | |
| 208 | .. index:: single: user; effective id |
| 209 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 210 | Return the current process's effective user id. |
| 211 | |
| 212 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 213 | |
| 214 | |
| 215 | .. function:: getgid() |
| 216 | |
| 217 | .. index:: single: process; group |
| 218 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 219 | Return the real group id of the current process. |
| 220 | |
| 221 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 222 | |
| 223 | |
Ross Lagerwall | b0ae53d | 2011-06-10 07:30:30 +0200 | [diff] [blame] | 224 | .. function:: getgrouplist(user, group) |
| 225 | |
| 226 | Return list of group ids that *user* belongs to. If *group* is not in the |
| 227 | list, it is included; typically, *group* is specified as the group ID |
| 228 | field from the password record for *user*. |
| 229 | |
| 230 | Availability: Unix. |
| 231 | |
| 232 | .. versionadded:: 3.3 |
| 233 | |
| 234 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 235 | .. function:: getgroups() |
| 236 | |
| 237 | Return list of supplemental group ids associated with the current process. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 238 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 239 | Availability: Unix. |
| 240 | |
| 241 | |
Antoine Pitrou | b7572f0 | 2009-12-02 20:46:48 +0000 | [diff] [blame] | 242 | .. function:: initgroups(username, gid) |
| 243 | |
| 244 | Call the system initgroups() to initialize the group access list with all of |
| 245 | the groups of which the specified username is a member, plus the specified |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 246 | group id. |
| 247 | |
| 248 | Availability: Unix. |
Antoine Pitrou | b7572f0 | 2009-12-02 20:46:48 +0000 | [diff] [blame] | 249 | |
| 250 | .. versionadded:: 3.2 |
| 251 | |
| 252 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 253 | .. function:: getlogin() |
| 254 | |
| 255 | Return the name of the user logged in on the controlling terminal of the |
Brian Curtin | e8e4b3b | 2010-09-23 20:04:14 +0000 | [diff] [blame] | 256 | process. For most purposes, it is more useful to use the environment variables |
| 257 | :envvar:`LOGNAME` or :envvar:`USERNAME` to find out who the user is, or |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 258 | ``pwd.getpwuid(os.getuid())[0]`` to get the login name of the currently |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 259 | effective user id. |
| 260 | |
Brian Curtin | e8e4b3b | 2010-09-23 20:04:14 +0000 | [diff] [blame] | 261 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 262 | |
| 263 | |
| 264 | .. function:: getpgid(pid) |
| 265 | |
| 266 | Return the process group id of the process with process id *pid*. If *pid* is 0, |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 267 | the process group id of the current process is returned. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 268 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 269 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 270 | |
| 271 | .. function:: getpgrp() |
| 272 | |
| 273 | .. index:: single: process; group |
| 274 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 275 | Return the id of the current process group. |
| 276 | |
| 277 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 278 | |
| 279 | |
| 280 | .. function:: getpid() |
| 281 | |
| 282 | .. index:: single: process; id |
| 283 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 284 | Return the current process id. |
| 285 | |
| 286 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 287 | |
| 288 | |
| 289 | .. function:: getppid() |
| 290 | |
| 291 | .. index:: single: process; id of parent |
| 292 | |
Amaury Forgeot d'Arc | 4b6fdf3 | 2010-09-07 21:31:17 +0000 | [diff] [blame] | 293 | Return the parent's process id. When the parent process has exited, on Unix |
| 294 | the id returned is the one of the init process (1), on Windows it is still |
| 295 | the same id, which may be already reused by another process. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 296 | |
Amaury Forgeot d'Arc | 4b6fdf3 | 2010-09-07 21:31:17 +0000 | [diff] [blame] | 297 | Availability: Unix, Windows |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 298 | |
Amaury Forgeot d'Arc | 4b6fdf3 | 2010-09-07 21:31:17 +0000 | [diff] [blame] | 299 | .. versionchanged:: 3.2 |
| 300 | Added support for Windows. |
Georg Brandl | 1b83a45 | 2009-11-28 11:12:26 +0000 | [diff] [blame] | 301 | |
Giampaolo Rodolà | 18e8bcb | 2011-02-25 20:57:54 +0000 | [diff] [blame] | 302 | .. function:: getpriority(which, who) |
| 303 | |
| 304 | .. index:: single: process; scheduling priority |
| 305 | |
| 306 | Get program scheduling priority. The value *which* is one of |
| 307 | :const:`PRIO_PROCESS`, :const:`PRIO_PGRP`, or :const:`PRIO_USER`, and *who* |
| 308 | is interpreted relative to *which* (a process identifier for |
| 309 | :const:`PRIO_PROCESS`, process group identifier for :const:`PRIO_PGRP`, and a |
| 310 | user ID for :const:`PRIO_USER`). A zero value for *who* denotes |
| 311 | (respectively) the calling process, the process group of the calling process, |
| 312 | or the real user ID of the calling process. |
| 313 | |
| 314 | Availability: Unix |
| 315 | |
| 316 | .. versionadded:: 3.3 |
| 317 | |
Gregory P. Smith | cf02c6a | 2009-11-27 17:54:17 +0000 | [diff] [blame] | 318 | .. function:: getresuid() |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 319 | |
| 320 | Return a tuple (ruid, euid, suid) denoting the current process's |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 321 | real, effective, and saved user ids. |
| 322 | |
| 323 | Availability: Unix. |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 324 | |
Georg Brandl | 1b83a45 | 2009-11-28 11:12:26 +0000 | [diff] [blame] | 325 | .. versionadded:: 3.2 |
| 326 | |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 327 | |
Gregory P. Smith | cf02c6a | 2009-11-27 17:54:17 +0000 | [diff] [blame] | 328 | .. function:: getresgid() |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 329 | |
| 330 | Return a tuple (rgid, egid, sgid) denoting the current process's |
Georg Brandl | a9b51d2 | 2010-09-05 17:07:12 +0000 | [diff] [blame] | 331 | real, effective, and saved group ids. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 332 | |
| 333 | Availability: Unix. |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 334 | |
Georg Brandl | 1b83a45 | 2009-11-28 11:12:26 +0000 | [diff] [blame] | 335 | .. versionadded:: 3.2 |
| 336 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 337 | |
| 338 | .. function:: getuid() |
| 339 | |
| 340 | .. index:: single: user; id |
| 341 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 342 | Return the current process's user id. |
| 343 | |
| 344 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 345 | |
| 346 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 347 | .. function:: getenv(key, default=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 348 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 349 | Return the value of the environment variable *key* if it exists, or |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 350 | *default* if it doesn't. *key*, *default* and the result are str. |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 351 | |
| 352 | On Unix, keys and values are decoded with :func:`sys.getfilesystemencoding` |
| 353 | and ``'surrogateescape'`` error handler. Use :func:`os.getenvb` if you |
| 354 | would like to use a different encoding. |
| 355 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 356 | Availability: most flavors of Unix, Windows. |
| 357 | |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 358 | |
| 359 | .. function:: getenvb(key, default=None) |
| 360 | |
| 361 | Return the value of the environment variable *key* if it exists, or |
| 362 | *default* if it doesn't. *key*, *default* and the result are bytes. |
Benjamin Peterson | 0d6fe51 | 2010-05-06 22:13:11 +0000 | [diff] [blame] | 363 | |
Victor Stinner | 84ae118 | 2010-05-06 22:05:07 +0000 | [diff] [blame] | 364 | Availability: most flavors of Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 365 | |
Benjamin Peterson | 0d6fe51 | 2010-05-06 22:13:11 +0000 | [diff] [blame] | 366 | .. versionadded:: 3.2 |
| 367 | |
Giampaolo Rodolà | 18e8bcb | 2011-02-25 20:57:54 +0000 | [diff] [blame] | 368 | .. data:: PRIO_PROCESS |
| 369 | PRIO_PGRP |
| 370 | PRIO_USER |
| 371 | |
| 372 | Parameters for :func:`getpriority` and :func:`setpriority` functions. |
| 373 | |
| 374 | Availability: Unix. |
| 375 | |
| 376 | .. versionadded:: 3.3 |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 377 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 378 | .. function:: putenv(key, value) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 379 | |
| 380 | .. index:: single: environment variables; setting |
| 381 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 382 | Set the environment variable named *key* to the string *value*. Such |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 383 | changes to the environment affect subprocesses started with :func:`os.system`, |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 384 | :func:`popen` or :func:`fork` and :func:`execv`. |
| 385 | |
| 386 | Availability: most flavors of Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 387 | |
| 388 | .. note:: |
| 389 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 390 | On some platforms, including FreeBSD and Mac OS X, setting ``environ`` may |
| 391 | cause memory leaks. Refer to the system documentation for putenv. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 392 | |
| 393 | When :func:`putenv` is supported, assignments to items in ``os.environ`` are |
| 394 | automatically translated into corresponding calls to :func:`putenv`; however, |
| 395 | calls to :func:`putenv` don't update ``os.environ``, so it is actually |
| 396 | preferable to assign to items of ``os.environ``. |
| 397 | |
| 398 | |
| 399 | .. function:: setegid(egid) |
| 400 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 401 | Set the current process's effective group id. |
| 402 | |
| 403 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 404 | |
| 405 | |
| 406 | .. function:: seteuid(euid) |
| 407 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 408 | Set the current process's effective user id. |
| 409 | |
| 410 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 411 | |
| 412 | |
| 413 | .. function:: setgid(gid) |
| 414 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 415 | Set the current process' group id. |
| 416 | |
| 417 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 418 | |
| 419 | |
| 420 | .. function:: setgroups(groups) |
| 421 | |
| 422 | Set the list of supplemental group ids associated with the current process to |
| 423 | *groups*. *groups* must be a sequence, and each element must be an integer |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 424 | identifying a group. This operation is typically available only to the superuser. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 425 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 426 | Availability: Unix. |
| 427 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 428 | |
| 429 | .. function:: setpgrp() |
| 430 | |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 431 | Call the system call :c:func:`setpgrp` or :c:func:`setpgrp(0, 0)` depending on |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 432 | which version is implemented (if any). See the Unix manual for the semantics. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 433 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 434 | Availability: Unix. |
| 435 | |
| 436 | |
| 437 | .. function:: setpgid(pid, pgrp) |
| 438 | |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 439 | Call the system call :c:func:`setpgid` to set the process group id of the |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 440 | process with id *pid* to the process group with id *pgrp*. See the Unix manual |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 441 | for the semantics. |
| 442 | |
| 443 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 444 | |
| 445 | |
Giampaolo Rodolà | 18e8bcb | 2011-02-25 20:57:54 +0000 | [diff] [blame] | 446 | .. function:: setpriority(which, who, priority) |
| 447 | |
| 448 | .. index:: single: process; scheduling priority |
| 449 | |
| 450 | Set program scheduling priority. The value *which* is one of |
| 451 | :const:`PRIO_PROCESS`, :const:`PRIO_PGRP`, or :const:`PRIO_USER`, and *who* |
| 452 | is interpreted relative to *which* (a process identifier for |
| 453 | :const:`PRIO_PROCESS`, process group identifier for :const:`PRIO_PGRP`, and a |
| 454 | user ID for :const:`PRIO_USER`). A zero value for *who* denotes |
| 455 | (respectively) the calling process, the process group of the calling process, |
| 456 | or the real user ID of the calling process. |
| 457 | *priority* is a value in the range -20 to 19. The default priority is 0; |
| 458 | lower priorities cause more favorable scheduling. |
| 459 | |
| 460 | Availability: Unix |
| 461 | |
| 462 | .. versionadded:: 3.3 |
| 463 | |
| 464 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 465 | .. function:: setregid(rgid, egid) |
| 466 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 467 | Set the current process's real and effective group ids. |
| 468 | |
| 469 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 470 | |
Georg Brandl | 1b83a45 | 2009-11-28 11:12:26 +0000 | [diff] [blame] | 471 | |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 472 | .. function:: setresgid(rgid, egid, sgid) |
| 473 | |
| 474 | Set the current process's real, effective, and saved group ids. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 475 | |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 476 | Availability: Unix. |
| 477 | |
Georg Brandl | 1b83a45 | 2009-11-28 11:12:26 +0000 | [diff] [blame] | 478 | .. versionadded:: 3.2 |
| 479 | |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 480 | |
| 481 | .. function:: setresuid(ruid, euid, suid) |
| 482 | |
| 483 | Set the current process's real, effective, and saved user ids. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 484 | |
Georg Brandl | 6faee4e | 2010-09-21 14:48:28 +0000 | [diff] [blame] | 485 | Availability: Unix. |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 486 | |
Georg Brandl | 1b83a45 | 2009-11-28 11:12:26 +0000 | [diff] [blame] | 487 | .. versionadded:: 3.2 |
| 488 | |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 489 | |
| 490 | .. function:: setreuid(ruid, euid) |
| 491 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 492 | Set the current process's real and effective user ids. |
| 493 | |
| 494 | Availability: Unix. |
Martin v. Löwis | 7aed61a | 2009-11-27 14:09:49 +0000 | [diff] [blame] | 495 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 496 | |
| 497 | .. function:: getsid(pid) |
| 498 | |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 499 | Call the system call :c:func:`getsid`. See the Unix manual for the semantics. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 500 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 501 | Availability: Unix. |
| 502 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 503 | |
| 504 | .. function:: setsid() |
| 505 | |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 506 | Call the system call :c:func:`setsid`. See the Unix manual for the semantics. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 507 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 508 | Availability: Unix. |
| 509 | |
| 510 | |
| 511 | .. function:: setuid(uid) |
| 512 | |
| 513 | .. index:: single: user; id, setting |
| 514 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 515 | Set the current process's user id. |
| 516 | |
| 517 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 518 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 519 | |
Christian Heimes | 5b5e81c | 2007-12-31 16:14:33 +0000 | [diff] [blame] | 520 | .. placed in this section since it relates to errno.... a little weak |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 521 | .. function:: strerror(code) |
| 522 | |
| 523 | Return the error message corresponding to the error code in *code*. |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 524 | On platforms where :c:func:`strerror` returns ``NULL`` when given an unknown |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 525 | error number, :exc:`ValueError` is raised. |
| 526 | |
| 527 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 528 | |
| 529 | |
Victor Stinner | b745a74 | 2010-05-18 17:17:23 +0000 | [diff] [blame] | 530 | .. data:: supports_bytes_environ |
| 531 | |
| 532 | True if the native OS type of the environment is bytes (eg. False on |
| 533 | Windows). |
| 534 | |
Victor Stinner | 8fddc9e | 2010-05-18 17:24:09 +0000 | [diff] [blame] | 535 | .. versionadded:: 3.2 |
| 536 | |
Victor Stinner | b745a74 | 2010-05-18 17:17:23 +0000 | [diff] [blame] | 537 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 538 | .. function:: umask(mask) |
| 539 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 540 | Set the current numeric umask and return the previous umask. |
| 541 | |
| 542 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 543 | |
| 544 | |
| 545 | .. function:: uname() |
| 546 | |
| 547 | .. index:: |
| 548 | single: gethostname() (in module socket) |
| 549 | single: gethostbyaddr() (in module socket) |
| 550 | |
| 551 | Return a 5-tuple containing information identifying the current operating |
| 552 | system. The tuple contains 5 strings: ``(sysname, nodename, release, version, |
| 553 | machine)``. Some systems truncate the nodename to 8 characters or to the |
| 554 | leading component; a better way to get the hostname is |
| 555 | :func:`socket.gethostname` or even |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 556 | ``socket.gethostbyaddr(socket.gethostname())``. |
| 557 | |
| 558 | Availability: recent flavors of Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 559 | |
| 560 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 561 | .. function:: unsetenv(key) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 562 | |
| 563 | .. index:: single: environment variables; deleting |
| 564 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 565 | Unset (delete) the environment variable named *key*. Such changes to the |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 566 | environment affect subprocesses started with :func:`os.system`, :func:`popen` or |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 567 | :func:`fork` and :func:`execv`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 568 | |
| 569 | When :func:`unsetenv` is supported, deletion of items in ``os.environ`` is |
| 570 | automatically translated into a corresponding call to :func:`unsetenv`; however, |
| 571 | calls to :func:`unsetenv` don't update ``os.environ``, so it is actually |
| 572 | preferable to delete items of ``os.environ``. |
| 573 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 574 | Availability: most flavors of Unix, Windows. |
| 575 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 576 | |
| 577 | .. _os-newstreams: |
| 578 | |
| 579 | File Object Creation |
| 580 | -------------------- |
| 581 | |
Antoine Pitrou | 11cb961 | 2010-09-15 11:11:28 +0000 | [diff] [blame] | 582 | These functions create new :term:`file objects <file object>`. (See also :func:`open`.) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 583 | |
| 584 | |
| 585 | .. function:: fdopen(fd[, mode[, bufsize]]) |
| 586 | |
| 587 | .. index:: single: I/O control; buffering |
| 588 | |
| 589 | Return an open file object connected to the file descriptor *fd*. The *mode* |
| 590 | and *bufsize* arguments have the same meaning as the corresponding arguments to |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 591 | the built-in :func:`open` function. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 592 | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 593 | When specified, the *mode* argument must start with one of the letters |
| 594 | ``'r'``, ``'w'``, or ``'a'``, otherwise a :exc:`ValueError` is raised. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 595 | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 596 | On Unix, when the *mode* argument starts with ``'a'``, the *O_APPEND* flag is |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 597 | set on the file descriptor (which the :c:func:`fdopen` implementation already |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 598 | does on most platforms). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 599 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 600 | Availability: Unix, Windows. |
| 601 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 602 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 603 | .. _os-fd-ops: |
| 604 | |
| 605 | File Descriptor Operations |
| 606 | -------------------------- |
| 607 | |
| 608 | These functions operate on I/O streams referenced using file descriptors. |
| 609 | |
| 610 | File descriptors are small integers corresponding to a file that has been opened |
| 611 | by the current process. For example, standard input is usually file descriptor |
| 612 | 0, standard output is 1, and standard error is 2. Further files opened by a |
| 613 | process will then be assigned 3, 4, 5, and so forth. The name "file descriptor" |
| 614 | is slightly deceptive; on Unix platforms, sockets and pipes are also referenced |
| 615 | by file descriptors. |
| 616 | |
Benjamin Peterson | 08bf91c | 2010-04-11 16:12:57 +0000 | [diff] [blame] | 617 | The :meth:`~file.fileno` method can be used to obtain the file descriptor |
Antoine Pitrou | 11cb961 | 2010-09-15 11:11:28 +0000 | [diff] [blame] | 618 | associated with a :term:`file object` when required. Note that using the file |
Benjamin Peterson | 08bf91c | 2010-04-11 16:12:57 +0000 | [diff] [blame] | 619 | descriptor directly will bypass the file object methods, ignoring aspects such |
| 620 | as internal buffering of data. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 621 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 622 | .. data:: AT_SYMLINK_NOFOLLOW |
| 623 | AT_EACCESS |
| 624 | AT_FDCWD |
| 625 | AT_REMOVEDIR |
| 626 | AT_SYMLINK_FOLLOW |
| 627 | UTIME_NOW |
| 628 | UTIME_OMIT |
| 629 | |
| 630 | These parameters are used as flags to the \*at family of functions. |
| 631 | |
| 632 | Availability: Unix. |
| 633 | |
| 634 | .. versionadded:: 3.3 |
| 635 | |
| 636 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 637 | .. function:: close(fd) |
| 638 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 639 | Close file descriptor *fd*. |
| 640 | |
| 641 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 642 | |
| 643 | .. note:: |
| 644 | |
| 645 | This function is intended for low-level I/O and must be applied to a file |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 646 | descriptor as returned by :func:`os.open` or :func:`pipe`. To close a "file |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 647 | object" returned by the built-in function :func:`open` or by :func:`popen` or |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 648 | :func:`fdopen`, use its :meth:`~file.close` method. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 649 | |
| 650 | |
Christian Heimes | fdab48e | 2008-01-20 09:06:41 +0000 | [diff] [blame] | 651 | .. function:: closerange(fd_low, fd_high) |
| 652 | |
| 653 | Close all file descriptors from *fd_low* (inclusive) to *fd_high* (exclusive), |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 654 | ignoring errors. Equivalent to:: |
Christian Heimes | fdab48e | 2008-01-20 09:06:41 +0000 | [diff] [blame] | 655 | |
Georg Brandl | c9a5a0e | 2009-09-01 07:34:27 +0000 | [diff] [blame] | 656 | for fd in range(fd_low, fd_high): |
Christian Heimes | fdab48e | 2008-01-20 09:06:41 +0000 | [diff] [blame] | 657 | try: |
| 658 | os.close(fd) |
| 659 | except OSError: |
| 660 | pass |
| 661 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 662 | Availability: Unix, Windows. |
| 663 | |
Christian Heimes | fdab48e | 2008-01-20 09:06:41 +0000 | [diff] [blame] | 664 | |
Georg Brandl | 81f1130 | 2007-12-21 08:45:42 +0000 | [diff] [blame] | 665 | .. function:: device_encoding(fd) |
| 666 | |
| 667 | Return a string describing the encoding of the device associated with *fd* |
| 668 | if it is connected to a terminal; else return :const:`None`. |
| 669 | |
| 670 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 671 | .. function:: dup(fd) |
| 672 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 673 | Return a duplicate of file descriptor *fd*. |
| 674 | |
| 675 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 676 | |
| 677 | |
| 678 | .. function:: dup2(fd, fd2) |
| 679 | |
| 680 | Duplicate file descriptor *fd* to *fd2*, closing the latter first if necessary. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 681 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 682 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 683 | |
| 684 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 685 | .. function:: faccessat(dirfd, path, mode, flags=0) |
| 686 | |
| 687 | Like :func:`access` but if *path* is relative, it is taken as relative to *dirfd*. |
| 688 | *flags* is optional and can be constructed by ORing together zero or more |
| 689 | of these values: :data:`AT_SYMLINK_NOFOLLOW`, :data:`AT_EACCESS`. |
| 690 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 691 | is interpreted relative to the current working directory. |
| 692 | |
| 693 | Availability: Unix. |
| 694 | |
| 695 | .. versionadded:: 3.3 |
| 696 | |
| 697 | |
Christian Heimes | 4e30a84 | 2007-11-30 22:12:06 +0000 | [diff] [blame] | 698 | .. function:: fchmod(fd, mode) |
| 699 | |
| 700 | Change the mode of the file given by *fd* to the numeric *mode*. See the docs |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 701 | for :func:`chmod` for possible values of *mode*. |
| 702 | |
| 703 | Availability: Unix. |
Christian Heimes | 4e30a84 | 2007-11-30 22:12:06 +0000 | [diff] [blame] | 704 | |
| 705 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 706 | .. function:: fchmodat(dirfd, path, mode, flags=0) |
| 707 | |
| 708 | Like :func:`chmod` but if *path* is relative, it is taken as relative to *dirfd*. |
| 709 | *flags* is optional and may be 0 or :data:`AT_SYMLINK_NOFOLLOW`. |
| 710 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 711 | is interpreted relative to the current working directory. |
| 712 | |
| 713 | Availability: Unix. |
| 714 | |
| 715 | .. versionadded:: 3.3 |
| 716 | |
| 717 | |
Christian Heimes | 4e30a84 | 2007-11-30 22:12:06 +0000 | [diff] [blame] | 718 | .. function:: fchown(fd, uid, gid) |
| 719 | |
| 720 | Change the owner and group id of the file given by *fd* to the numeric *uid* |
| 721 | and *gid*. To leave one of the ids unchanged, set it to -1. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 722 | |
Christian Heimes | 4e30a84 | 2007-11-30 22:12:06 +0000 | [diff] [blame] | 723 | Availability: Unix. |
| 724 | |
| 725 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 726 | .. function:: fchownat(dirfd, path, uid, gid, flags=0) |
| 727 | |
| 728 | Like :func:`chown` but if *path* is relative, it is taken as relative to *dirfd*. |
| 729 | *flags* is optional and may be 0 or :data:`AT_SYMLINK_NOFOLLOW`. |
| 730 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 731 | is interpreted relative to the current working directory. |
| 732 | |
| 733 | Availability: Unix. |
| 734 | |
| 735 | .. versionadded:: 3.3 |
| 736 | |
| 737 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 738 | .. function:: fdatasync(fd) |
| 739 | |
| 740 | Force write of file with filedescriptor *fd* to disk. Does not force update of |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 741 | metadata. |
| 742 | |
| 743 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 744 | |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 745 | .. note:: |
| 746 | This function is not available on MacOS. |
| 747 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 748 | |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 749 | .. function:: fgetxattr(fd, attr) |
| 750 | |
| 751 | This works exactly like :func:`getxattr` but operates on a file descriptor, |
| 752 | *fd*, instead of a path. |
| 753 | |
| 754 | Availability: Linux |
| 755 | |
| 756 | .. versionadded:: 3.3 |
| 757 | |
| 758 | |
| 759 | .. function:: flistxattr(fd) |
| 760 | |
| 761 | This is exactly like :func:`listxattr` but operates on a file descriptor, |
| 762 | *fd*, instead of a path. |
| 763 | |
| 764 | Availability: Linux |
| 765 | |
| 766 | .. versionadded:: 3.3 |
| 767 | |
| 768 | |
Antoine Pitrou | 8250e23 | 2011-02-25 23:41:16 +0000 | [diff] [blame] | 769 | .. function:: fdlistdir(fd) |
| 770 | |
| 771 | Like :func:`listdir`, but uses a file descriptor instead and always returns |
| 772 | strings. After execution of this function, *fd* will be closed. |
| 773 | |
| 774 | Availability: Unix. |
| 775 | |
| 776 | .. versionadded:: 3.3 |
| 777 | |
| 778 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 779 | .. function:: fexecve(fd, args, env) |
| 780 | |
| 781 | Execute the program specified by a file descriptor *fd* with arguments given |
| 782 | by *args* and environment given by *env*, replacing the current process. |
| 783 | *args* and *env* are given as in :func:`execve`. |
| 784 | |
| 785 | Availability: Unix. |
| 786 | |
| 787 | .. versionadded:: 3.3 |
| 788 | |
| 789 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 790 | .. function:: fpathconf(fd, name) |
| 791 | |
| 792 | Return system configuration information relevant to an open file. *name* |
| 793 | specifies the configuration value to retrieve; it may be a string which is the |
| 794 | name of a defined system value; these names are specified in a number of |
| 795 | standards (POSIX.1, Unix 95, Unix 98, and others). Some platforms define |
| 796 | additional names as well. The names known to the host operating system are |
| 797 | given in the ``pathconf_names`` dictionary. For configuration variables not |
| 798 | included in that mapping, passing an integer for *name* is also accepted. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 799 | |
| 800 | If *name* is a string and is not known, :exc:`ValueError` is raised. If a |
| 801 | specific value for *name* is not supported by the host system, even if it is |
| 802 | included in ``pathconf_names``, an :exc:`OSError` is raised with |
| 803 | :const:`errno.EINVAL` for the error number. |
| 804 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 805 | Availability: Unix. |
| 806 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 807 | |
| 808 | .. function:: fstat(fd) |
| 809 | |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 810 | Return status for file descriptor *fd*, like :func:`~os.stat`. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 811 | |
| 812 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 813 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 814 | .. function:: fstatat(dirfd, path, flags=0) |
| 815 | |
| 816 | Like :func:`stat` but if *path* is relative, it is taken as relative to *dirfd*. |
| 817 | *flags* is optional and may be 0 or :data:`AT_SYMLINK_NOFOLLOW`. |
| 818 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 819 | is interpreted relative to the current working directory. |
| 820 | |
| 821 | Availability: Unix. |
| 822 | |
| 823 | .. versionadded:: 3.3 |
| 824 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 825 | |
| 826 | .. function:: fstatvfs(fd) |
| 827 | |
| 828 | Return information about the filesystem containing the file associated with file |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 829 | descriptor *fd*, like :func:`statvfs`. |
| 830 | |
| 831 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 832 | |
| 833 | |
| 834 | .. function:: fsync(fd) |
| 835 | |
| 836 | Force write of file with filedescriptor *fd* to disk. On Unix, this calls the |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 837 | native :c:func:`fsync` function; on Windows, the MS :c:func:`_commit` function. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 838 | |
Antoine Pitrou | 11cb961 | 2010-09-15 11:11:28 +0000 | [diff] [blame] | 839 | If you're starting with a buffered Python :term:`file object` *f*, first do |
| 840 | ``f.flush()``, and then do ``os.fsync(f.fileno())``, to ensure that all internal |
| 841 | buffers associated with *f* are written to disk. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 842 | |
| 843 | Availability: Unix, and Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 844 | |
| 845 | |
| 846 | .. function:: ftruncate(fd, length) |
| 847 | |
| 848 | Truncate the file corresponding to file descriptor *fd*, so that it is at most |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 849 | *length* bytes in size. |
| 850 | |
| 851 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 852 | |
| 853 | |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 854 | .. function:: fremovexattr(fd, attr) |
| 855 | |
| 856 | This works exactly like :func:`removexattr` but operates on a file |
| 857 | descriptor, *fd*, instead of a path. |
| 858 | |
| 859 | Availability: Linux |
| 860 | |
| 861 | .. versionadded:: 3.3 |
| 862 | |
| 863 | |
| 864 | .. function:: fsetxattr(fd, attr, value, flags=0) |
| 865 | |
| 866 | This works exactly like :func:`setxattr` but on a file descriptor, *fd*, |
| 867 | instead of a path. |
| 868 | |
| 869 | |
| 870 | Availability: Linux |
| 871 | |
| 872 | .. versionadded:: 3.3 |
| 873 | |
| 874 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 875 | .. function:: futimesat(dirfd, path, (atime, mtime)) |
| 876 | futimesat(dirfd, path, None) |
| 877 | |
| 878 | Like :func:`utime` but if *path* is relative, it is taken as relative to *dirfd*. |
| 879 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 880 | is interpreted relative to the current working directory. |
| 881 | |
| 882 | Availability: Unix. |
| 883 | |
| 884 | .. versionadded:: 3.3 |
| 885 | |
| 886 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 887 | .. function:: futimens(fd, (atime_sec, atime_nsec), (mtime_sec, mtime_nsec)) |
| 888 | futimens(fd, None, None) |
| 889 | |
| 890 | Updates the timestamps of a file specified by the file descriptor *fd*, with |
| 891 | nanosecond precision. |
| 892 | The second form sets *atime* and *mtime* to the current time. |
| 893 | If *atime_nsec* or *mtime_nsec* is specified as :data:`UTIME_NOW`, the corresponding |
| 894 | timestamp is updated to the current time. |
| 895 | If *atime_nsec* or *mtime_nsec* is specified as :data:`UTIME_OMIT`, the corresponding |
| 896 | timestamp is not updated. |
| 897 | |
| 898 | Availability: Unix. |
| 899 | |
| 900 | .. versionadded:: 3.3 |
| 901 | |
| 902 | |
| 903 | .. data:: UTIME_NOW |
| 904 | UTIME_OMIT |
| 905 | |
| 906 | Flags used with :func:`futimens` to specify that the timestamp must be |
| 907 | updated either to the current time or not updated at all. |
| 908 | |
| 909 | Availability: Unix. |
| 910 | |
| 911 | .. versionadded:: 3.3 |
| 912 | |
| 913 | |
| 914 | .. function:: futimes(fd, (atime, mtime)) |
| 915 | futimes(fd, None) |
| 916 | |
| 917 | Set the access and modified time of the file specified by the file |
| 918 | descriptor *fd* to the given values. If the second form is used, set the |
| 919 | access and modified times to the current time. |
| 920 | |
| 921 | Availability: Unix. |
| 922 | |
| 923 | .. versionadded:: 3.3 |
| 924 | |
| 925 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 926 | .. function:: isatty(fd) |
| 927 | |
| 928 | Return ``True`` if the file descriptor *fd* is open and connected to a |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 929 | tty(-like) device, else ``False``. |
| 930 | |
| 931 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 932 | |
| 933 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 934 | .. function:: linkat(srcfd, srcpath, dstfd, dstpath, flags=0) |
| 935 | |
| 936 | Like :func:`link` but if *srcpath* is relative, it is taken as relative to *srcfd* |
| 937 | and if *dstpath* is relative, it is taken as relative to *dstfd*. |
| 938 | *flags* is optional and may be 0 or :data:`AT_SYMLINK_FOLLOW`. |
| 939 | If *srcpath* is relative and *srcfd* is the special value :data:`AT_FDCWD`, then |
| 940 | *srcpath* is interpreted relative to the current working directory. This |
| 941 | also applies for *dstpath*. |
| 942 | |
| 943 | Availability: Unix. |
| 944 | |
| 945 | .. versionadded:: 3.3 |
| 946 | |
| 947 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 948 | .. function:: lockf(fd, cmd, len) |
| 949 | |
| 950 | Apply, test or remove a POSIX lock on an open file descriptor. |
| 951 | *fd* is an open file descriptor. |
| 952 | *cmd* specifies the command to use - one of :data:`F_LOCK`, :data:`F_TLOCK`, |
| 953 | :data:`F_ULOCK` or :data:`F_TEST`. |
| 954 | *len* specifies the section of the file to lock. |
| 955 | |
| 956 | Availability: Unix. |
| 957 | |
| 958 | .. versionadded:: 3.3 |
| 959 | |
| 960 | |
| 961 | .. data:: F_LOCK |
| 962 | F_TLOCK |
| 963 | F_ULOCK |
| 964 | F_TEST |
| 965 | |
| 966 | Flags that specify what action :func:`lockf` will take. |
| 967 | |
| 968 | Availability: Unix. |
| 969 | |
| 970 | .. versionadded:: 3.3 |
| 971 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 972 | .. function:: lseek(fd, pos, how) |
| 973 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 974 | Set the current position of file descriptor *fd* to position *pos*, modified |
| 975 | by *how*: :const:`SEEK_SET` or ``0`` to set the position relative to the |
| 976 | beginning of the file; :const:`SEEK_CUR` or ``1`` to set it relative to the |
| 977 | current position; :const:`os.SEEK_END` or ``2`` to set it relative to the end of |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 978 | the file. |
| 979 | |
| 980 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 981 | |
| 982 | |
Georg Brandl | 8569e58 | 2010-05-19 20:57:08 +0000 | [diff] [blame] | 983 | .. data:: SEEK_SET |
| 984 | SEEK_CUR |
| 985 | SEEK_END |
| 986 | |
| 987 | Parameters to the :func:`lseek` function. Their values are 0, 1, and 2, |
| 988 | respectively. Availability: Windows, Unix. |
| 989 | |
| 990 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 991 | .. function:: mkdirat(dirfd, path, mode=0o777) |
| 992 | |
| 993 | Like :func:`mkdir` but if *path* is relative, it is taken as relative to *dirfd*. |
| 994 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 995 | is interpreted relative to the current working directory. |
| 996 | |
| 997 | Availability: Unix. |
| 998 | |
| 999 | .. versionadded:: 3.3 |
| 1000 | |
| 1001 | |
| 1002 | .. function:: mkfifoat(dirfd, path, mode=0o666) |
| 1003 | |
| 1004 | Like :func:`mkfifo` but if *path* is relative, it is taken as relative to *dirfd*. |
| 1005 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 1006 | is interpreted relative to the current working directory. |
| 1007 | |
| 1008 | Availability: Unix. |
| 1009 | |
| 1010 | .. versionadded:: 3.3 |
| 1011 | |
| 1012 | |
| 1013 | .. function:: mknodat(dirfd, path, mode=0o600, device=0) |
| 1014 | |
| 1015 | Like :func:`mknod` but if *path* is relative, it is taken as relative to *dirfd*. |
| 1016 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 1017 | is interpreted relative to the current working directory. |
| 1018 | |
| 1019 | Availability: Unix. |
| 1020 | |
| 1021 | .. versionadded:: 3.3 |
| 1022 | |
| 1023 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1024 | .. function:: open(file, flags[, mode]) |
| 1025 | |
Georg Brandl | f4a4123 | 2008-05-26 17:55:52 +0000 | [diff] [blame] | 1026 | Open the file *file* and set various flags according to *flags* and possibly |
| 1027 | its mode according to *mode*. The default *mode* is ``0o777`` (octal), and |
| 1028 | the current umask value is first masked out. Return the file descriptor for |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1029 | the newly opened file. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1030 | |
| 1031 | For a description of the flag and mode values, see the C run-time documentation; |
| 1032 | flag constants (like :const:`O_RDONLY` and :const:`O_WRONLY`) are defined in |
Georg Brandl | 8569e58 | 2010-05-19 20:57:08 +0000 | [diff] [blame] | 1033 | this module too (see :ref:`open-constants`). In particular, on Windows adding |
| 1034 | :const:`O_BINARY` is needed to open files in binary mode. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1035 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1036 | Availability: Unix, Windows. |
| 1037 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1038 | .. note:: |
| 1039 | |
Georg Brandl | 502d9a5 | 2009-07-26 15:02:41 +0000 | [diff] [blame] | 1040 | This function is intended for low-level I/O. For normal usage, use the |
Antoine Pitrou | 11cb961 | 2010-09-15 11:11:28 +0000 | [diff] [blame] | 1041 | built-in function :func:`open`, which returns a :term:`file object` with |
Jeroen Ruigrok van der Werven | 9c558bcf | 2010-07-13 14:47:01 +0000 | [diff] [blame] | 1042 | :meth:`~file.read` and :meth:`~file.write` methods (and many more). To |
Antoine Pitrou | 11cb961 | 2010-09-15 11:11:28 +0000 | [diff] [blame] | 1043 | wrap a file descriptor in a file object, use :func:`fdopen`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1044 | |
| 1045 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 1046 | .. function:: openat(dirfd, path, flags, mode=0o777) |
| 1047 | |
| 1048 | Like :func:`open` but if *path* is relative, it is taken as relative to *dirfd*. |
| 1049 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 1050 | is interpreted relative to the current working directory. |
| 1051 | |
| 1052 | Availability: Unix. |
| 1053 | |
| 1054 | .. versionadded:: 3.3 |
| 1055 | |
| 1056 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1057 | .. function:: openpty() |
| 1058 | |
| 1059 | .. index:: module: pty |
| 1060 | |
| 1061 | Open a new pseudo-terminal pair. Return a pair of file descriptors ``(master, |
| 1062 | slave)`` for the pty and the tty, respectively. For a (slightly) more portable |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1063 | approach, use the :mod:`pty` module. |
| 1064 | |
| 1065 | Availability: some flavors of Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1066 | |
| 1067 | |
| 1068 | .. function:: pipe() |
| 1069 | |
| 1070 | Create a pipe. Return a pair of file descriptors ``(r, w)`` usable for reading |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1071 | and writing, respectively. |
| 1072 | |
| 1073 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1074 | |
| 1075 | |
Charles-François Natali | 368f34b | 2011-06-06 19:49:47 +0200 | [diff] [blame] | 1076 | .. function:: pipe2(flags) |
Charles-François Natali | daafdd5 | 2011-05-29 20:07:40 +0200 | [diff] [blame] | 1077 | |
| 1078 | Create a pipe with *flags* set atomically. |
Charles-François Natali | 368f34b | 2011-06-06 19:49:47 +0200 | [diff] [blame] | 1079 | *flags* can be constructed by ORing together one or more of these values: |
| 1080 | :data:`O_NONBLOCK`, :data:`O_CLOEXEC`. |
Charles-François Natali | daafdd5 | 2011-05-29 20:07:40 +0200 | [diff] [blame] | 1081 | Return a pair of file descriptors ``(r, w)`` usable for reading and writing, |
| 1082 | respectively. |
| 1083 | |
| 1084 | Availability: some flavors of Unix. |
| 1085 | |
| 1086 | .. versionadded:: 3.3 |
| 1087 | |
| 1088 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 1089 | .. function:: posix_fallocate(fd, offset, len) |
| 1090 | |
| 1091 | Ensures that enough disk space is allocated for the file specified by *fd* |
| 1092 | starting from *offset* and continuing for *len* bytes. |
| 1093 | |
| 1094 | Availability: Unix. |
| 1095 | |
| 1096 | .. versionadded:: 3.3 |
| 1097 | |
| 1098 | |
| 1099 | .. function:: posix_fadvise(fd, offset, len, advice) |
| 1100 | |
| 1101 | Announces an intention to access data in a specific pattern thus allowing |
| 1102 | the kernel to make optimizations. |
| 1103 | The advice applies to the region of the file specified by *fd* starting at |
| 1104 | *offset* and continuing for *len* bytes. |
| 1105 | *advice* is one of :data:`POSIX_FADV_NORMAL`, :data:`POSIX_FADV_SEQUENTIAL`, |
| 1106 | :data:`POSIX_FADV_RANDOM`, :data:`POSIX_FADV_NOREUSE`, |
| 1107 | :data:`POSIX_FADV_WILLNEED` or :data:`POSIX_FADV_DONTNEED`. |
| 1108 | |
| 1109 | Availability: Unix. |
| 1110 | |
| 1111 | .. versionadded:: 3.3 |
| 1112 | |
| 1113 | |
| 1114 | .. data:: POSIX_FADV_NORMAL |
| 1115 | POSIX_FADV_SEQUENTIAL |
| 1116 | POSIX_FADV_RANDOM |
| 1117 | POSIX_FADV_NOREUSE |
| 1118 | POSIX_FADV_WILLNEED |
| 1119 | POSIX_FADV_DONTNEED |
| 1120 | |
| 1121 | Flags that can be used in *advice* in :func:`posix_fadvise` that specify |
| 1122 | the access pattern that is likely to be used. |
| 1123 | |
| 1124 | Availability: Unix. |
| 1125 | |
| 1126 | .. versionadded:: 3.3 |
| 1127 | |
| 1128 | |
| 1129 | .. function:: pread(fd, buffersize, offset) |
| 1130 | |
| 1131 | Read from a file descriptor, *fd*, at a position of *offset*. It will read up |
| 1132 | to *buffersize* number of bytes. The file offset remains unchanged. |
| 1133 | |
| 1134 | Availability: Unix. |
| 1135 | |
| 1136 | .. versionadded:: 3.3 |
| 1137 | |
| 1138 | |
| 1139 | .. function:: pwrite(fd, string, offset) |
| 1140 | |
| 1141 | Write *string* to a file descriptor, *fd*, from *offset*, leaving the file |
| 1142 | offset unchanged. |
| 1143 | |
| 1144 | Availability: Unix. |
| 1145 | |
| 1146 | .. versionadded:: 3.3 |
| 1147 | |
| 1148 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1149 | .. function:: read(fd, n) |
| 1150 | |
Georg Brandl | b90be69 | 2009-07-29 16:14:16 +0000 | [diff] [blame] | 1151 | Read at most *n* bytes from file descriptor *fd*. Return a bytestring containing the |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1152 | bytes read. If the end of the file referred to by *fd* has been reached, an |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1153 | empty bytes object is returned. |
| 1154 | |
| 1155 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1156 | |
| 1157 | .. note:: |
| 1158 | |
| 1159 | This function is intended for low-level I/O and must be applied to a file |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 1160 | descriptor as returned by :func:`os.open` or :func:`pipe`. To read a "file object" |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1161 | returned by the built-in function :func:`open` or by :func:`popen` or |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 1162 | :func:`fdopen`, or :data:`sys.stdin`, use its :meth:`~file.read` or |
| 1163 | :meth:`~file.readline` methods. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1164 | |
| 1165 | |
Giampaolo Rodolà | c9c2c8b | 2011-02-25 14:39:16 +0000 | [diff] [blame] | 1166 | .. function:: sendfile(out, in, offset, nbytes) |
| 1167 | sendfile(out, in, offset, nbytes, headers=None, trailers=None, flags=0) |
| 1168 | |
| 1169 | Copy *nbytes* bytes from file descriptor *in* to file descriptor *out* |
| 1170 | starting at *offset*. |
| 1171 | Return the number of bytes sent. When EOF is reached return 0. |
| 1172 | |
| 1173 | The first function notation is supported by all platforms that define |
| 1174 | :func:`sendfile`. |
| 1175 | |
| 1176 | On Linux, if *offset* is given as ``None``, the bytes are read from the |
| 1177 | current position of *in* and the position of *in* is updated. |
| 1178 | |
| 1179 | The second case may be used on Mac OS X and FreeBSD where *headers* and |
| 1180 | *trailers* are arbitrary sequences of buffers that are written before and |
| 1181 | after the data from *in* is written. It returns the same as the first case. |
| 1182 | |
| 1183 | On Mac OS X and FreeBSD, a value of 0 for *nbytes* specifies to send until |
| 1184 | the end of *in* is reached. |
| 1185 | |
| 1186 | On Solaris, *out* may be the file descriptor of a regular file or the file |
| 1187 | descriptor of a socket. On all other platforms, *out* must be the file |
| 1188 | descriptor of an open socket. |
| 1189 | |
| 1190 | Availability: Unix. |
| 1191 | |
| 1192 | .. versionadded:: 3.3 |
| 1193 | |
| 1194 | |
| 1195 | .. data:: SF_NODISKIO |
| 1196 | SF_MNOWAIT |
| 1197 | SF_SYNC |
| 1198 | |
| 1199 | Parameters to the :func:`sendfile` function, if the implementation supports |
| 1200 | them. |
| 1201 | |
| 1202 | Availability: Unix. |
| 1203 | |
| 1204 | .. versionadded:: 3.3 |
| 1205 | |
| 1206 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 1207 | .. function:: readlinkat(dirfd, path) |
| 1208 | |
| 1209 | Like :func:`readlink` but if *path* is relative, it is taken as relative to *dirfd*. |
| 1210 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 1211 | is interpreted relative to the current working directory. |
| 1212 | |
| 1213 | Availability: Unix. |
| 1214 | |
| 1215 | .. versionadded:: 3.3 |
| 1216 | |
| 1217 | |
| 1218 | .. function:: renameat(olddirfd, oldpath, newdirfd, newpath) |
| 1219 | |
| 1220 | Like :func:`rename` but if *oldpath* is relative, it is taken as relative to |
| 1221 | *olddirfd* and if *newpath* is relative, it is taken as relative to *newdirfd*. |
| 1222 | If *oldpath* is relative and *olddirfd* is the special value :data:`AT_FDCWD`, then |
| 1223 | *oldpath* is interpreted relative to the current working directory. This |
| 1224 | also applies for *newpath*. |
| 1225 | |
| 1226 | Availability: Unix. |
| 1227 | |
| 1228 | .. versionadded:: 3.3 |
| 1229 | |
| 1230 | |
| 1231 | .. function:: symlinkat(src, dstfd, dst) |
| 1232 | |
| 1233 | Like :func:`symlink` but if *dst* is relative, it is taken as relative to *dstfd*. |
| 1234 | If *dst* is relative and *dstfd* is the special value :data:`AT_FDCWD`, then *dst* |
| 1235 | is interpreted relative to the current working directory. |
| 1236 | |
| 1237 | Availability: Unix. |
| 1238 | |
| 1239 | .. versionadded:: 3.3 |
| 1240 | |
| 1241 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 1242 | .. function:: readv(fd, buffers) |
| 1243 | |
| 1244 | Read from a file descriptor into a number of writable buffers. *buffers* is |
| 1245 | an arbitrary sequence of writable buffers. Returns the total number of bytes |
| 1246 | read. |
| 1247 | |
| 1248 | Availability: Unix. |
| 1249 | |
| 1250 | .. versionadded:: 3.3 |
| 1251 | |
| 1252 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1253 | .. function:: tcgetpgrp(fd) |
| 1254 | |
| 1255 | Return the process group associated with the terminal given by *fd* (an open |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1256 | file descriptor as returned by :func:`os.open`). |
| 1257 | |
| 1258 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1259 | |
| 1260 | |
| 1261 | .. function:: tcsetpgrp(fd, pg) |
| 1262 | |
| 1263 | Set the process group associated with the terminal given by *fd* (an open file |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1264 | descriptor as returned by :func:`os.open`) to *pg*. |
| 1265 | |
| 1266 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1267 | |
| 1268 | |
| 1269 | .. function:: ttyname(fd) |
| 1270 | |
| 1271 | Return a string which specifies the terminal device associated with |
Georg Brandl | 9afde1c | 2007-11-01 20:32:30 +0000 | [diff] [blame] | 1272 | file descriptor *fd*. If *fd* is not associated with a terminal device, an |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1273 | exception is raised. |
| 1274 | |
| 1275 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1276 | |
| 1277 | |
Antoine Pitrou | f65132d | 2011-02-25 23:25:17 +0000 | [diff] [blame] | 1278 | .. function:: unlinkat(dirfd, path, flags=0) |
| 1279 | |
| 1280 | Like :func:`unlink` but if *path* is relative, it is taken as relative to *dirfd*. |
| 1281 | *flags* is optional and may be 0 or :data:`AT_REMOVEDIR`. If :data:`AT_REMOVEDIR` is |
| 1282 | specified, :func:`unlinkat` behaves like :func:`rmdir`. |
| 1283 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 1284 | is interpreted relative to the current working directory. |
| 1285 | |
| 1286 | Availability: Unix. |
| 1287 | |
| 1288 | .. versionadded:: 3.3 |
| 1289 | |
| 1290 | |
| 1291 | .. function:: utimensat(dirfd, path, (atime_sec, atime_nsec), (mtime_sec, mtime_nsec), flags) |
| 1292 | utimensat(dirfd, path, None, None, flags) |
| 1293 | |
| 1294 | Updates the timestamps of a file with nanosecond precision. |
| 1295 | The second form sets *atime* and *mtime* to the current time. |
| 1296 | If *atime_nsec* or *mtime_nsec* is specified as :data:`UTIME_NOW`, the corresponding |
| 1297 | timestamp is updated to the current time. |
| 1298 | If *atime_nsec* or *mtime_nsec* is specified as :data:`UTIME_OMIT`, the corresponding |
| 1299 | timestamp is not updated. |
| 1300 | If *path* is relative, it is taken as relative to *dirfd*. |
| 1301 | *flags* is optional and may be 0 or :data:`AT_SYMLINK_NOFOLLOW`. |
| 1302 | If *path* is relative and *dirfd* is the special value :data:`AT_FDCWD`, then *path* |
| 1303 | is interpreted relative to the current working directory. |
| 1304 | |
| 1305 | Availability: Unix. |
| 1306 | |
| 1307 | .. versionadded:: 3.3 |
| 1308 | |
| 1309 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1310 | .. function:: write(fd, str) |
| 1311 | |
Georg Brandl | b90be69 | 2009-07-29 16:14:16 +0000 | [diff] [blame] | 1312 | Write the bytestring in *str* to file descriptor *fd*. Return the number of |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1313 | bytes actually written. |
| 1314 | |
| 1315 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1316 | |
| 1317 | .. note:: |
| 1318 | |
| 1319 | This function is intended for low-level I/O and must be applied to a file |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 1320 | descriptor as returned by :func:`os.open` or :func:`pipe`. To write a "file |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1321 | object" returned by the built-in function :func:`open` or by :func:`popen` or |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 1322 | :func:`fdopen`, or :data:`sys.stdout` or :data:`sys.stderr`, use its |
| 1323 | :meth:`~file.write` method. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1324 | |
Georg Brandl | 8569e58 | 2010-05-19 20:57:08 +0000 | [diff] [blame] | 1325 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 1326 | .. function:: writev(fd, buffers) |
| 1327 | |
| 1328 | Write the the contents of *buffers* to file descriptor *fd*, where *buffers* |
| 1329 | is an arbitrary sequence of buffers. |
| 1330 | Returns the total number of bytes written. |
| 1331 | |
| 1332 | Availability: Unix. |
| 1333 | |
| 1334 | .. versionadded:: 3.3 |
| 1335 | |
| 1336 | |
Georg Brandl | 8569e58 | 2010-05-19 20:57:08 +0000 | [diff] [blame] | 1337 | .. _open-constants: |
| 1338 | |
| 1339 | ``open()`` flag constants |
| 1340 | ~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 1341 | |
Georg Brandl | af265f4 | 2008-12-07 15:06:20 +0000 | [diff] [blame] | 1342 | The following constants are options for the *flags* parameter to the |
Benjamin Peterson | fa0d703 | 2009-06-01 22:42:33 +0000 | [diff] [blame] | 1343 | :func:`~os.open` function. They can be combined using the bitwise OR operator |
Georg Brandl | af265f4 | 2008-12-07 15:06:20 +0000 | [diff] [blame] | 1344 | ``|``. Some of them are not available on all platforms. For descriptions of |
| 1345 | their availability and use, consult the :manpage:`open(2)` manual page on Unix |
Doug Hellmann | eb097fc | 2009-09-20 20:56:56 +0000 | [diff] [blame] | 1346 | or `the MSDN <http://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx>`_ on Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1347 | |
| 1348 | |
| 1349 | .. data:: O_RDONLY |
| 1350 | O_WRONLY |
| 1351 | O_RDWR |
| 1352 | O_APPEND |
| 1353 | O_CREAT |
| 1354 | O_EXCL |
| 1355 | O_TRUNC |
| 1356 | |
Georg Brandl | af265f4 | 2008-12-07 15:06:20 +0000 | [diff] [blame] | 1357 | These constants are available on Unix and Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1358 | |
| 1359 | |
| 1360 | .. data:: O_DSYNC |
| 1361 | O_RSYNC |
| 1362 | O_SYNC |
| 1363 | O_NDELAY |
| 1364 | O_NONBLOCK |
| 1365 | O_NOCTTY |
| 1366 | O_SHLOCK |
| 1367 | O_EXLOCK |
Charles-François Natali | 1e045b1 | 2011-05-22 20:42:32 +0200 | [diff] [blame] | 1368 | O_CLOEXEC |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1369 | |
Georg Brandl | af265f4 | 2008-12-07 15:06:20 +0000 | [diff] [blame] | 1370 | These constants are only available on Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1371 | |
| 1372 | |
| 1373 | .. data:: O_BINARY |
Guido van Rossum | 0d3fb8a | 2007-11-26 23:23:18 +0000 | [diff] [blame] | 1374 | O_NOINHERIT |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1375 | O_SHORT_LIVED |
| 1376 | O_TEMPORARY |
| 1377 | O_RANDOM |
| 1378 | O_SEQUENTIAL |
| 1379 | O_TEXT |
| 1380 | |
Georg Brandl | af265f4 | 2008-12-07 15:06:20 +0000 | [diff] [blame] | 1381 | These constants are only available on Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1382 | |
| 1383 | |
Alexandre Vassalotti | bee3253 | 2008-05-16 18:15:12 +0000 | [diff] [blame] | 1384 | .. data:: O_ASYNC |
| 1385 | O_DIRECT |
Guido van Rossum | 0d3fb8a | 2007-11-26 23:23:18 +0000 | [diff] [blame] | 1386 | O_DIRECTORY |
| 1387 | O_NOFOLLOW |
| 1388 | O_NOATIME |
| 1389 | |
Georg Brandl | af265f4 | 2008-12-07 15:06:20 +0000 | [diff] [blame] | 1390 | These constants are GNU extensions and not present if they are not defined by |
| 1391 | the C library. |
Guido van Rossum | 0d3fb8a | 2007-11-26 23:23:18 +0000 | [diff] [blame] | 1392 | |
| 1393 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1394 | .. _os-file-dir: |
| 1395 | |
| 1396 | Files and Directories |
| 1397 | --------------------- |
| 1398 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1399 | .. function:: access(path, mode) |
| 1400 | |
| 1401 | Use the real uid/gid to test for access to *path*. Note that most operations |
| 1402 | will use the effective uid/gid, therefore this routine can be used in a |
| 1403 | suid/sgid environment to test if the invoking user has the specified access to |
| 1404 | *path*. *mode* should be :const:`F_OK` to test the existence of *path*, or it |
| 1405 | can be the inclusive OR of one or more of :const:`R_OK`, :const:`W_OK`, and |
| 1406 | :const:`X_OK` to test permissions. Return :const:`True` if access is allowed, |
| 1407 | :const:`False` if not. See the Unix man page :manpage:`access(2)` for more |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1408 | information. |
| 1409 | |
| 1410 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1411 | |
| 1412 | .. note:: |
| 1413 | |
Georg Brandl | 502d9a5 | 2009-07-26 15:02:41 +0000 | [diff] [blame] | 1414 | Using :func:`access` to check if a user is authorized to e.g. open a file |
| 1415 | before actually doing so using :func:`open` creates a security hole, |
| 1416 | because the user might exploit the short time interval between checking |
Benjamin Peterson | 249b508 | 2011-05-20 11:41:13 -0500 | [diff] [blame] | 1417 | and opening the file to manipulate it. It's preferable to use :term:`EAFP` |
| 1418 | techniques. For example:: |
| 1419 | |
| 1420 | if os.access("myfile", os.R_OK): |
| 1421 | with open("myfile") as fp: |
| 1422 | return fp.read() |
| 1423 | return "some default data" |
| 1424 | |
| 1425 | is better written as:: |
| 1426 | |
| 1427 | try: |
| 1428 | fp = open("myfile") |
Antoine Pitrou | 62ab10a0 | 2011-10-12 20:10:51 +0200 | [diff] [blame] | 1429 | except PermissionError: |
| 1430 | return "some default data" |
Benjamin Peterson | 249b508 | 2011-05-20 11:41:13 -0500 | [diff] [blame] | 1431 | else: |
| 1432 | with fp: |
| 1433 | return fp.read() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1434 | |
| 1435 | .. note:: |
| 1436 | |
| 1437 | I/O operations may fail even when :func:`access` indicates that they would |
| 1438 | succeed, particularly for operations on network filesystems which may have |
| 1439 | permissions semantics beyond the usual POSIX permission-bit model. |
| 1440 | |
| 1441 | |
| 1442 | .. data:: F_OK |
| 1443 | |
| 1444 | Value to pass as the *mode* parameter of :func:`access` to test the existence of |
| 1445 | *path*. |
| 1446 | |
| 1447 | |
| 1448 | .. data:: R_OK |
| 1449 | |
| 1450 | Value to include in the *mode* parameter of :func:`access` to test the |
| 1451 | readability of *path*. |
| 1452 | |
| 1453 | |
| 1454 | .. data:: W_OK |
| 1455 | |
| 1456 | Value to include in the *mode* parameter of :func:`access` to test the |
| 1457 | writability of *path*. |
| 1458 | |
| 1459 | |
| 1460 | .. data:: X_OK |
| 1461 | |
| 1462 | Value to include in the *mode* parameter of :func:`access` to determine if |
| 1463 | *path* can be executed. |
| 1464 | |
| 1465 | |
| 1466 | .. function:: chdir(path) |
| 1467 | |
| 1468 | .. index:: single: directory; changing |
| 1469 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1470 | Change the current working directory to *path*. |
| 1471 | |
| 1472 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1473 | |
| 1474 | |
| 1475 | .. function:: fchdir(fd) |
| 1476 | |
| 1477 | Change the current working directory to the directory represented by the file |
| 1478 | descriptor *fd*. The descriptor must refer to an opened directory, not an open |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1479 | file. |
| 1480 | |
| 1481 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1482 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1483 | |
| 1484 | .. function:: getcwd() |
| 1485 | |
Martin v. Löwis | 011e842 | 2009-05-05 04:43:17 +0000 | [diff] [blame] | 1486 | Return a string representing the current working directory. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1487 | |
Martin v. Löwis | 011e842 | 2009-05-05 04:43:17 +0000 | [diff] [blame] | 1488 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1489 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1490 | |
Martin v. Löwis | a731b99 | 2008-10-07 06:36:31 +0000 | [diff] [blame] | 1491 | .. function:: getcwdb() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1492 | |
Georg Brandl | 76e5538 | 2008-10-08 16:34:57 +0000 | [diff] [blame] | 1493 | Return a bytestring representing the current working directory. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1494 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 1495 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1496 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1497 | |
| 1498 | .. function:: chflags(path, flags) |
| 1499 | |
| 1500 | Set the flags of *path* to the numeric *flags*. *flags* may take a combination |
| 1501 | (bitwise OR) of the following values (as defined in the :mod:`stat` module): |
| 1502 | |
R David Murray | 3017806 | 2011-03-10 17:18:33 -0500 | [diff] [blame] | 1503 | * :data:`stat.UF_NODUMP` |
| 1504 | * :data:`stat.UF_IMMUTABLE` |
| 1505 | * :data:`stat.UF_APPEND` |
| 1506 | * :data:`stat.UF_OPAQUE` |
| 1507 | * :data:`stat.UF_NOUNLINK` |
Ned Deily | 3eb67d5 | 2011-06-28 00:00:28 -0700 | [diff] [blame] | 1508 | * :data:`stat.UF_COMPRESSED` |
| 1509 | * :data:`stat.UF_HIDDEN` |
R David Murray | 3017806 | 2011-03-10 17:18:33 -0500 | [diff] [blame] | 1510 | * :data:`stat.SF_ARCHIVED` |
| 1511 | * :data:`stat.SF_IMMUTABLE` |
| 1512 | * :data:`stat.SF_APPEND` |
| 1513 | * :data:`stat.SF_NOUNLINK` |
| 1514 | * :data:`stat.SF_SNAPSHOT` |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1515 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 1516 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1517 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1518 | |
| 1519 | .. function:: chroot(path) |
| 1520 | |
| 1521 | Change the root directory of the current process to *path*. Availability: |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 1522 | Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1523 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1524 | |
| 1525 | .. function:: chmod(path, mode) |
| 1526 | |
| 1527 | Change the mode of *path* to the numeric *mode*. *mode* may take one of the |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 1528 | following values (as defined in the :mod:`stat` module) or bitwise ORed |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1529 | combinations of them: |
| 1530 | |
Alexandre Vassalotti | c22c6f2 | 2009-07-21 00:51:58 +0000 | [diff] [blame] | 1531 | * :data:`stat.S_ISUID` |
| 1532 | * :data:`stat.S_ISGID` |
| 1533 | * :data:`stat.S_ENFMT` |
| 1534 | * :data:`stat.S_ISVTX` |
| 1535 | * :data:`stat.S_IREAD` |
| 1536 | * :data:`stat.S_IWRITE` |
| 1537 | * :data:`stat.S_IEXEC` |
| 1538 | * :data:`stat.S_IRWXU` |
| 1539 | * :data:`stat.S_IRUSR` |
| 1540 | * :data:`stat.S_IWUSR` |
| 1541 | * :data:`stat.S_IXUSR` |
| 1542 | * :data:`stat.S_IRWXG` |
| 1543 | * :data:`stat.S_IRGRP` |
| 1544 | * :data:`stat.S_IWGRP` |
| 1545 | * :data:`stat.S_IXGRP` |
| 1546 | * :data:`stat.S_IRWXO` |
| 1547 | * :data:`stat.S_IROTH` |
| 1548 | * :data:`stat.S_IWOTH` |
| 1549 | * :data:`stat.S_IXOTH` |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1550 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 1551 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1552 | |
| 1553 | .. note:: |
| 1554 | |
| 1555 | Although Windows supports :func:`chmod`, you can only set the file's read-only |
| 1556 | flag with it (via the ``stat.S_IWRITE`` and ``stat.S_IREAD`` |
| 1557 | constants or a corresponding integer value). All other bits are |
| 1558 | ignored. |
| 1559 | |
| 1560 | |
| 1561 | .. function:: chown(path, uid, gid) |
| 1562 | |
| 1563 | Change the owner and group id of *path* to the numeric *uid* and *gid*. To leave |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1564 | one of the ids unchanged, set it to -1. |
| 1565 | |
Sandro Tosi | d902a14 | 2011-08-22 23:28:27 +0200 | [diff] [blame] | 1566 | See :func:`shutil.chown` for a higher-level function that accepts names in |
| 1567 | addition to numeric ids. |
| 1568 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1569 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1570 | |
| 1571 | |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 1572 | .. function:: getxattr(path, attr) |
| 1573 | |
| 1574 | Return the value of the extended filesystem attribute *attr* for |
| 1575 | *path*. *attr* can be bytes or str. If it is str, it is encoded with the |
| 1576 | filesystem encoding. |
| 1577 | |
| 1578 | Availability: Linux |
| 1579 | |
| 1580 | .. versionadded:: 3.3 |
| 1581 | |
| 1582 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1583 | .. function:: lchflags(path, flags) |
| 1584 | |
| 1585 | Set the flags of *path* to the numeric *flags*, like :func:`chflags`, but do not |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1586 | follow symbolic links. |
| 1587 | |
| 1588 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1589 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1590 | |
Christian Heimes | 9385266 | 2007-12-01 12:22:32 +0000 | [diff] [blame] | 1591 | .. function:: lchmod(path, mode) |
| 1592 | |
| 1593 | Change the mode of *path* to the numeric *mode*. If path is a symlink, this |
| 1594 | affects the symlink rather than the target. See the docs for :func:`chmod` |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1595 | for possible values of *mode*. |
| 1596 | |
| 1597 | Availability: Unix. |
Christian Heimes | 9385266 | 2007-12-01 12:22:32 +0000 | [diff] [blame] | 1598 | |
Christian Heimes | 9385266 | 2007-12-01 12:22:32 +0000 | [diff] [blame] | 1599 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1600 | .. function:: lchown(path, uid, gid) |
| 1601 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 1602 | Change the owner and group id of *path* to the numeric *uid* and *gid*. This |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1603 | function will not follow symbolic links. |
| 1604 | |
| 1605 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1606 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1607 | |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 1608 | .. function:: lgetxattr(path, attr) |
| 1609 | |
| 1610 | This works exactly like :func:`getxattr` but doesn't follow symlinks. |
| 1611 | |
| 1612 | Availability: Linux |
| 1613 | |
| 1614 | .. versionadded:: 3.3 |
| 1615 | |
| 1616 | |
Benjamin Peterson | 5879d41 | 2009-03-30 14:51:56 +0000 | [diff] [blame] | 1617 | .. function:: link(source, link_name) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1618 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1619 | Create a hard link pointing to *source* named *link_name*. |
| 1620 | |
Brian Curtin | 1b9df39 | 2010-11-24 20:24:31 +0000 | [diff] [blame] | 1621 | Availability: Unix, Windows. |
| 1622 | |
| 1623 | .. versionchanged:: 3.2 |
| 1624 | Added Windows support. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1625 | |
| 1626 | |
Martin v. Löwis | 9c71f90 | 2010-07-24 10:09:11 +0000 | [diff] [blame] | 1627 | .. function:: listdir(path='.') |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1628 | |
Benjamin Peterson | 4469d0c | 2008-11-30 22:46:23 +0000 | [diff] [blame] | 1629 | Return a list containing the names of the entries in the directory given by |
Martin v. Löwis | 9c71f90 | 2010-07-24 10:09:11 +0000 | [diff] [blame] | 1630 | *path* (default: ``'.'``). The list is in arbitrary order. It does not include the special |
Benjamin Peterson | 4469d0c | 2008-11-30 22:46:23 +0000 | [diff] [blame] | 1631 | entries ``'.'`` and ``'..'`` even if they are present in the directory. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1632 | |
Martin v. Löwis | 011e842 | 2009-05-05 04:43:17 +0000 | [diff] [blame] | 1633 | This function can be called with a bytes or string argument, and returns |
| 1634 | filenames of the same datatype. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1635 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1636 | Availability: Unix, Windows. |
| 1637 | |
Martin v. Löwis | c9e1c7d | 2010-07-23 12:16:41 +0000 | [diff] [blame] | 1638 | .. versionchanged:: 3.2 |
| 1639 | The *path* parameter became optional. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1640 | |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 1641 | |
| 1642 | .. function:: listxattr(path) |
| 1643 | |
| 1644 | Return a list of the extended filesystem attributes on *path*. Attributes are |
| 1645 | returned as string decoded with the filesystem encoding. |
| 1646 | |
| 1647 | Availability: Linux |
| 1648 | |
| 1649 | .. versionadded:: 3.3 |
| 1650 | |
| 1651 | |
| 1652 | .. function:: llistxattr(path) |
| 1653 | |
| 1654 | This works exactly like :func:`listxattr` but doesn't follow symlinks. |
| 1655 | |
| 1656 | Availability: Linux |
| 1657 | |
| 1658 | .. versionadded:: 3.3 |
| 1659 | |
| 1660 | |
Victor Stinner | 69db2db | 2011-10-14 00:07:53 +0200 | [diff] [blame^] | 1661 | .. function:: lremovexattr(path, attr) |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 1662 | |
Victor Stinner | 69db2db | 2011-10-14 00:07:53 +0200 | [diff] [blame^] | 1663 | This works exactly like :func:`removexattr` but doesn't follow symlinks. |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 1664 | |
| 1665 | Availability: Linux |
| 1666 | |
| 1667 | .. versionadded:: 3.3 |
| 1668 | |
| 1669 | |
| 1670 | .. function:: lsetxattr(path, attr, value, flags=0) |
| 1671 | |
| 1672 | This works exactly like :func:`setxattr` but doesn't follow symlinks. |
| 1673 | |
| 1674 | Availability: Linux |
| 1675 | |
| 1676 | .. versionadded:: 3.3 |
| 1677 | |
| 1678 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1679 | .. function:: lstat(path) |
| 1680 | |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 1681 | Perform the equivalent of an :c:func:`lstat` system call on the given path. |
| 1682 | Similar to :func:`~os.stat`, but does not follow symbolic links. On |
| 1683 | platforms that do not support symbolic links, this is an alias for |
| 1684 | :func:`~os.stat`. |
Brian Curtin | c739569 | 2010-07-09 15:15:09 +0000 | [diff] [blame] | 1685 | |
Georg Brandl | b382337 | 2010-07-10 08:58:37 +0000 | [diff] [blame] | 1686 | .. versionchanged:: 3.2 |
| 1687 | Added support for Windows 6.0 (Vista) symbolic links. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1688 | |
| 1689 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 1690 | .. function:: lutimes(path, (atime, mtime)) |
| 1691 | lutimes(path, None) |
| 1692 | |
| 1693 | Like :func:`utime`, but if *path* is a symbolic link, it is not |
| 1694 | dereferenced. |
| 1695 | |
| 1696 | Availability: Unix. |
| 1697 | |
| 1698 | .. versionadded:: 3.3 |
| 1699 | |
| 1700 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1701 | .. function:: mkfifo(path[, mode]) |
| 1702 | |
Georg Brandl | f4a4123 | 2008-05-26 17:55:52 +0000 | [diff] [blame] | 1703 | Create a FIFO (a named pipe) named *path* with numeric mode *mode*. The |
| 1704 | default *mode* is ``0o666`` (octal). The current umask value is first masked |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1705 | out from the mode. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1706 | |
| 1707 | FIFOs are pipes that can be accessed like regular files. FIFOs exist until they |
| 1708 | are deleted (for example with :func:`os.unlink`). Generally, FIFOs are used as |
| 1709 | rendezvous between "client" and "server" type processes: the server opens the |
| 1710 | FIFO for reading, and the client opens it for writing. Note that :func:`mkfifo` |
| 1711 | doesn't open the FIFO --- it just creates the rendezvous point. |
| 1712 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1713 | Availability: Unix. |
| 1714 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1715 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 1716 | .. function:: mknod(filename[, mode=0o600[, device]]) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1717 | |
| 1718 | Create a filesystem node (file, device special file or named pipe) named |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 1719 | *filename*. *mode* specifies both the permissions to use and the type of node |
| 1720 | to be created, being combined (bitwise OR) with one of ``stat.S_IFREG``, |
| 1721 | ``stat.S_IFCHR``, ``stat.S_IFBLK``, and ``stat.S_IFIFO`` (those constants are |
| 1722 | available in :mod:`stat`). For ``stat.S_IFCHR`` and ``stat.S_IFBLK``, |
| 1723 | *device* defines the newly created device special file (probably using |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1724 | :func:`os.makedev`), otherwise it is ignored. |
| 1725 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1726 | |
| 1727 | .. function:: major(device) |
| 1728 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 1729 | Extract the device major number from a raw device number (usually the |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 1730 | :attr:`st_dev` or :attr:`st_rdev` field from :c:type:`stat`). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1731 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1732 | |
| 1733 | .. function:: minor(device) |
| 1734 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 1735 | Extract the device minor number from a raw device number (usually the |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 1736 | :attr:`st_dev` or :attr:`st_rdev` field from :c:type:`stat`). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1737 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1738 | |
| 1739 | .. function:: makedev(major, minor) |
| 1740 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 1741 | Compose a raw device number from the major and minor device numbers. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1742 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1743 | |
| 1744 | .. function:: mkdir(path[, mode]) |
| 1745 | |
Georg Brandl | f4a4123 | 2008-05-26 17:55:52 +0000 | [diff] [blame] | 1746 | Create a directory named *path* with numeric mode *mode*. The default *mode* |
| 1747 | is ``0o777`` (octal). On some systems, *mode* is ignored. Where it is used, |
Benjamin Peterson | d7c3ed5 | 2010-06-27 22:32:30 +0000 | [diff] [blame] | 1748 | the current umask value is first masked out. If the directory already |
| 1749 | exists, :exc:`OSError` is raised. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1750 | |
Guido van Rossum | 2cc30da | 2007-11-02 23:46:40 +0000 | [diff] [blame] | 1751 | It is also possible to create temporary directories; see the |
| 1752 | :mod:`tempfile` module's :func:`tempfile.mkdtemp` function. |
| 1753 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1754 | Availability: Unix, Windows. |
| 1755 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1756 | |
Georg Brandl | c167368 | 2010-12-02 09:06:12 +0000 | [diff] [blame] | 1757 | .. function:: makedirs(path, mode=0o777, exist_ok=False) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1758 | |
| 1759 | .. index:: |
| 1760 | single: directory; creating |
| 1761 | single: UNC paths; and os.makedirs() |
| 1762 | |
| 1763 | Recursive directory creation function. Like :func:`mkdir`, but makes all |
Terry Reedy | 5a22b65 | 2010-12-02 07:05:56 +0000 | [diff] [blame] | 1764 | intermediate-level directories needed to contain the leaf directory. If |
Georg Brandl | c167368 | 2010-12-02 09:06:12 +0000 | [diff] [blame] | 1765 | the target directory with the same mode as specified already exists, |
Terry Reedy | 5a22b65 | 2010-12-02 07:05:56 +0000 | [diff] [blame] | 1766 | raises an :exc:`OSError` exception if *exist_ok* is False, otherwise no |
| 1767 | exception is raised. If the directory cannot be created in other cases, |
| 1768 | raises an :exc:`OSError` exception. The default *mode* is ``0o777`` (octal). |
Georg Brandl | c167368 | 2010-12-02 09:06:12 +0000 | [diff] [blame] | 1769 | On some systems, *mode* is ignored. Where it is used, the current umask |
Terry Reedy | 5a22b65 | 2010-12-02 07:05:56 +0000 | [diff] [blame] | 1770 | value is first masked out. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1771 | |
| 1772 | .. note:: |
| 1773 | |
Georg Brandl | c167368 | 2010-12-02 09:06:12 +0000 | [diff] [blame] | 1774 | :func:`makedirs` will become confused if the path elements to create |
| 1775 | include :data:`pardir`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1776 | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 1777 | This function handles UNC paths correctly. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1778 | |
Terry Reedy | 5a22b65 | 2010-12-02 07:05:56 +0000 | [diff] [blame] | 1779 | .. versionadded:: 3.2 |
| 1780 | The *exist_ok* parameter. |
| 1781 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1782 | |
| 1783 | .. function:: pathconf(path, name) |
| 1784 | |
| 1785 | Return system configuration information relevant to a named file. *name* |
| 1786 | specifies the configuration value to retrieve; it may be a string which is the |
| 1787 | name of a defined system value; these names are specified in a number of |
| 1788 | standards (POSIX.1, Unix 95, Unix 98, and others). Some platforms define |
| 1789 | additional names as well. The names known to the host operating system are |
| 1790 | given in the ``pathconf_names`` dictionary. For configuration variables not |
| 1791 | included in that mapping, passing an integer for *name* is also accepted. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1792 | |
| 1793 | If *name* is a string and is not known, :exc:`ValueError` is raised. If a |
| 1794 | specific value for *name* is not supported by the host system, even if it is |
| 1795 | included in ``pathconf_names``, an :exc:`OSError` is raised with |
| 1796 | :const:`errno.EINVAL` for the error number. |
| 1797 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1798 | Availability: Unix. |
| 1799 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1800 | |
| 1801 | .. data:: pathconf_names |
| 1802 | |
| 1803 | Dictionary mapping names accepted by :func:`pathconf` and :func:`fpathconf` to |
| 1804 | the integer values defined for those names by the host operating system. This |
| 1805 | can be used to determine the set of names known to the system. Availability: |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 1806 | Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1807 | |
| 1808 | |
| 1809 | .. function:: readlink(path) |
| 1810 | |
| 1811 | Return a string representing the path to which the symbolic link points. The |
| 1812 | result may be either an absolute or relative pathname; if it is relative, it may |
| 1813 | be converted to an absolute pathname using ``os.path.join(os.path.dirname(path), |
| 1814 | result)``. |
| 1815 | |
Georg Brandl | 76e5538 | 2008-10-08 16:34:57 +0000 | [diff] [blame] | 1816 | If the *path* is a string object, the result will also be a string object, |
| 1817 | and the call may raise an UnicodeDecodeError. If the *path* is a bytes |
| 1818 | object, the result will be a bytes object. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1819 | |
Brian Curtin | c739569 | 2010-07-09 15:15:09 +0000 | [diff] [blame] | 1820 | Availability: Unix, Windows |
| 1821 | |
Georg Brandl | b382337 | 2010-07-10 08:58:37 +0000 | [diff] [blame] | 1822 | .. versionchanged:: 3.2 |
| 1823 | Added support for Windows 6.0 (Vista) symbolic links. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1824 | |
| 1825 | |
| 1826 | .. function:: remove(path) |
| 1827 | |
Georg Brandl | a6053b4 | 2009-09-01 08:11:14 +0000 | [diff] [blame] | 1828 | Remove (delete) the file *path*. If *path* is a directory, :exc:`OSError` is |
| 1829 | raised; see :func:`rmdir` below to remove a directory. This is identical to |
| 1830 | the :func:`unlink` function documented below. On Windows, attempting to |
| 1831 | remove a file that is in use causes an exception to be raised; on Unix, the |
| 1832 | directory entry is removed but the storage allocated to the file is not made |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1833 | available until the original file is no longer in use. |
| 1834 | |
| 1835 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1836 | |
| 1837 | |
| 1838 | .. function:: removedirs(path) |
| 1839 | |
| 1840 | .. index:: single: directory; deleting |
| 1841 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 1842 | Remove directories recursively. Works like :func:`rmdir` except that, if the |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1843 | leaf directory is successfully removed, :func:`removedirs` tries to |
| 1844 | successively remove every parent directory mentioned in *path* until an error |
| 1845 | is raised (which is ignored, because it generally means that a parent directory |
| 1846 | is not empty). For example, ``os.removedirs('foo/bar/baz')`` will first remove |
| 1847 | the directory ``'foo/bar/baz'``, and then remove ``'foo/bar'`` and ``'foo'`` if |
| 1848 | they are empty. Raises :exc:`OSError` if the leaf directory could not be |
| 1849 | successfully removed. |
| 1850 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1851 | |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 1852 | .. function:: removexattr(path, attr) |
| 1853 | |
| 1854 | Removes the extended filesystem attribute *attr* from *path*. *attr* should |
| 1855 | be bytes or str. If it is a string, it is encoded with the filesystem |
| 1856 | encoding. |
| 1857 | |
| 1858 | Availability: Linux |
| 1859 | |
| 1860 | .. versionadded:: 3.3 |
| 1861 | |
| 1862 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1863 | .. function:: rename(src, dst) |
| 1864 | |
| 1865 | Rename the file or directory *src* to *dst*. If *dst* is a directory, |
| 1866 | :exc:`OSError` will be raised. On Unix, if *dst* exists and is a file, it will |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 1867 | be replaced silently if the user has permission. The operation may fail on some |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1868 | Unix flavors if *src* and *dst* are on different filesystems. If successful, |
| 1869 | the renaming will be an atomic operation (this is a POSIX requirement). On |
| 1870 | Windows, if *dst* already exists, :exc:`OSError` will be raised even if it is a |
| 1871 | file; there may be no way to implement an atomic rename when *dst* names an |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1872 | existing file. |
| 1873 | |
| 1874 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1875 | |
| 1876 | |
| 1877 | .. function:: renames(old, new) |
| 1878 | |
| 1879 | Recursive directory or file renaming function. Works like :func:`rename`, except |
| 1880 | creation of any intermediate directories needed to make the new pathname good is |
| 1881 | attempted first. After the rename, directories corresponding to rightmost path |
| 1882 | segments of the old name will be pruned away using :func:`removedirs`. |
| 1883 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1884 | .. note:: |
| 1885 | |
| 1886 | This function can fail with the new directory structure made if you lack |
| 1887 | permissions needed to remove the leaf directory or file. |
| 1888 | |
| 1889 | |
| 1890 | .. function:: rmdir(path) |
| 1891 | |
Georg Brandl | a6053b4 | 2009-09-01 08:11:14 +0000 | [diff] [blame] | 1892 | Remove (delete) the directory *path*. Only works when the directory is |
| 1893 | empty, otherwise, :exc:`OSError` is raised. In order to remove whole |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 1894 | directory trees, :func:`shutil.rmtree` can be used. |
| 1895 | |
| 1896 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1897 | |
| 1898 | |
Benjamin Peterson | 799bd80 | 2011-08-31 22:15:17 -0400 | [diff] [blame] | 1899 | .. data:: XATTR_SIZE_MAX |
| 1900 | |
| 1901 | The maximum size the value of an extended attribute can be. Currently, this |
| 1902 | is 64 kilobytes on Linux. |
| 1903 | |
| 1904 | |
| 1905 | .. data:: XATTR_CREATE |
| 1906 | |
| 1907 | This is a possible value for the flags argument in :func:`setxattr`. It |
| 1908 | indicates the operation must create an attribute. |
| 1909 | |
| 1910 | |
| 1911 | .. data:: XATTR_REPLACE |
| 1912 | |
| 1913 | This is a possible value for the flags argument in :func:`setxattr`. It |
| 1914 | indicates the operation must replace an existing attribute. |
| 1915 | |
| 1916 | |
| 1917 | .. function:: setxattr(path, attr, value, flags=0) |
| 1918 | |
| 1919 | Set the extended filesystem attribute *attr* on *path* to *value*. *attr* |
| 1920 | must be a bytes or str with no embedded NULs. If it is str, it is encoded |
| 1921 | with the filesystem encoding. *flags* may be :data:`XATTR_REPLACE` or |
| 1922 | :data:`XATTR_CREATE`. If :data:`XATTR_REPLACE` is given and the attribute |
| 1923 | does not exist, ``EEXISTS`` will be raised. If :data:`XATTR_CREATE` is given |
| 1924 | and the attribute already exists, the attribute will not be created and |
| 1925 | ``ENODATA`` will be raised. |
| 1926 | |
| 1927 | Availability: Linux |
| 1928 | |
| 1929 | .. note:: |
| 1930 | |
| 1931 | A bug in Linux kernel versions less than 2.6.39 caused the flags argument |
| 1932 | to be ignored on some filesystems. |
| 1933 | |
| 1934 | .. versionadded:: 3.3 |
| 1935 | |
| 1936 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1937 | .. function:: stat(path) |
| 1938 | |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 1939 | Perform the equivalent of a :c:func:`stat` system call on the given path. |
| 1940 | (This function follows symlinks; to stat a symlink use :func:`lstat`.) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1941 | |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 1942 | The return value is an object whose attributes correspond to the members |
| 1943 | of the :c:type:`stat` structure, namely: |
| 1944 | |
| 1945 | * :attr:`st_mode` - protection bits, |
| 1946 | * :attr:`st_ino` - inode number, |
| 1947 | * :attr:`st_dev` - device, |
| 1948 | * :attr:`st_nlink` - number of hard links, |
| 1949 | * :attr:`st_uid` - user id of owner, |
| 1950 | * :attr:`st_gid` - group id of owner, |
| 1951 | * :attr:`st_size` - size of file, in bytes, |
| 1952 | * :attr:`st_atime` - time of most recent access, |
| 1953 | * :attr:`st_mtime` - time of most recent content modification, |
| 1954 | * :attr:`st_ctime` - platform dependent; time of most recent metadata change on |
| 1955 | Unix, or the time of creation on Windows) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1956 | |
| 1957 | On some Unix systems (such as Linux), the following attributes may also be |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 1958 | available: |
| 1959 | |
| 1960 | * :attr:`st_blocks` - number of blocks allocated for file |
| 1961 | * :attr:`st_blksize` - filesystem blocksize |
| 1962 | * :attr:`st_rdev` - type of device if an inode device |
| 1963 | * :attr:`st_flags` - user defined flags for file |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1964 | |
| 1965 | On other Unix systems (such as FreeBSD), the following attributes may be |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 1966 | available (but may be only filled out if root tries to use them): |
| 1967 | |
| 1968 | * :attr:`st_gen` - file generation number |
| 1969 | * :attr:`st_birthtime` - time of file creation |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1970 | |
| 1971 | On Mac OS systems, the following attributes may also be available: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1972 | |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 1973 | * :attr:`st_rsize` |
| 1974 | * :attr:`st_creator` |
| 1975 | * :attr:`st_type` |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1976 | |
| 1977 | .. note:: |
| 1978 | |
Senthil Kumaran | 3aac179 | 2011-07-04 11:43:51 -0700 | [diff] [blame] | 1979 | The exact meaning and resolution of the :attr:`st_atime`, |
Senthil Kumaran | a6bac95 | 2011-07-04 11:28:30 -0700 | [diff] [blame] | 1980 | :attr:`st_mtime`, and :attr:`st_ctime` attributes depend on the operating |
| 1981 | system and the file system. For example, on Windows systems using the FAT |
| 1982 | or FAT32 file systems, :attr:`st_mtime` has 2-second resolution, and |
| 1983 | :attr:`st_atime` has only 1-day resolution. See your operating system |
| 1984 | documentation for details. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1985 | |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 1986 | For backward compatibility, the return value of :func:`~os.stat` is also accessible |
| 1987 | as a tuple of at least 10 integers giving the most important (and portable) |
| 1988 | members of the :c:type:`stat` structure, in the order :attr:`st_mode`, |
| 1989 | :attr:`st_ino`, :attr:`st_dev`, :attr:`st_nlink`, :attr:`st_uid`, |
| 1990 | :attr:`st_gid`, :attr:`st_size`, :attr:`st_atime`, :attr:`st_mtime`, |
| 1991 | :attr:`st_ctime`. More items may be added at the end by some implementations. |
| 1992 | |
| 1993 | .. index:: module: stat |
| 1994 | |
| 1995 | The standard module :mod:`stat` defines functions and constants that are useful |
| 1996 | for extracting information from a :c:type:`stat` structure. (On Windows, some |
| 1997 | items are filled with dummy values.) |
| 1998 | |
| 1999 | Example:: |
| 2000 | |
| 2001 | >>> import os |
| 2002 | >>> statinfo = os.stat('somefile.txt') |
| 2003 | >>> statinfo |
Raymond Hettinger | 8f0ae9a | 2011-02-18 00:53:55 +0000 | [diff] [blame] | 2004 | posix.stat_result(st_mode=33188, st_ino=7876932, st_dev=234881026, |
| 2005 | st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295, |
| 2006 | st_mtime=1297230027, st_ctime=1297230027) |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 2007 | >>> statinfo.st_size |
Raymond Hettinger | 8f0ae9a | 2011-02-18 00:53:55 +0000 | [diff] [blame] | 2008 | 264 |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 2009 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2010 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2011 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2012 | |
| 2013 | .. function:: stat_float_times([newvalue]) |
| 2014 | |
| 2015 | Determine whether :class:`stat_result` represents time stamps as float objects. |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 2016 | If *newvalue* is ``True``, future calls to :func:`~os.stat` return floats, if it is |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2017 | ``False``, future calls return ints. If *newvalue* is omitted, return the |
| 2018 | current setting. |
| 2019 | |
| 2020 | For compatibility with older Python versions, accessing :class:`stat_result` as |
| 2021 | a tuple always returns integers. |
| 2022 | |
Georg Brandl | 55ac8f0 | 2007-09-01 13:51:09 +0000 | [diff] [blame] | 2023 | Python now returns float values by default. Applications which do not work |
| 2024 | correctly with floating point time stamps can use this function to restore the |
| 2025 | old behaviour. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2026 | |
| 2027 | The resolution of the timestamps (that is the smallest possible fraction) |
| 2028 | depends on the system. Some systems only support second resolution; on these |
| 2029 | systems, the fraction will always be zero. |
| 2030 | |
| 2031 | It is recommended that this setting is only changed at program startup time in |
| 2032 | the *__main__* module; libraries should never change this setting. If an |
| 2033 | application uses a library that works incorrectly if floating point time stamps |
| 2034 | are processed, this application should turn the feature off until the library |
| 2035 | has been corrected. |
| 2036 | |
| 2037 | |
| 2038 | .. function:: statvfs(path) |
| 2039 | |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 2040 | Perform a :c:func:`statvfs` system call on the given path. The return value is |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2041 | an object whose attributes describe the filesystem on the given path, and |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 2042 | correspond to the members of the :c:type:`statvfs` structure, namely: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2043 | :attr:`f_bsize`, :attr:`f_frsize`, :attr:`f_blocks`, :attr:`f_bfree`, |
| 2044 | :attr:`f_bavail`, :attr:`f_files`, :attr:`f_ffree`, :attr:`f_favail`, |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2045 | :attr:`f_flag`, :attr:`f_namemax`. |
| 2046 | |
Andrew M. Kuchling | 4ea04a3 | 2010-08-18 22:30:34 +0000 | [diff] [blame] | 2047 | Two module-level constants are defined for the :attr:`f_flag` attribute's |
| 2048 | bit-flags: if :const:`ST_RDONLY` is set, the filesystem is mounted |
| 2049 | read-only, and if :const:`ST_NOSUID` is set, the semantics of |
| 2050 | setuid/setgid bits are disabled or not supported. |
| 2051 | |
| 2052 | .. versionchanged:: 3.2 |
| 2053 | The :const:`ST_RDONLY` and :const:`ST_NOSUID` constants were added. |
| 2054 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2055 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2056 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2057 | |
Benjamin Peterson | 5879d41 | 2009-03-30 14:51:56 +0000 | [diff] [blame] | 2058 | .. function:: symlink(source, link_name) |
Georg Brandl | 64a41ed | 2010-10-06 08:52:48 +0000 | [diff] [blame] | 2059 | symlink(source, link_name, target_is_directory=False) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2060 | |
Brian Curtin | c739569 | 2010-07-09 15:15:09 +0000 | [diff] [blame] | 2061 | Create a symbolic link pointing to *source* named *link_name*. |
| 2062 | |
Georg Brandl | 64a41ed | 2010-10-06 08:52:48 +0000 | [diff] [blame] | 2063 | On Windows, symlink version takes an additional optional parameter, |
| 2064 | *target_is_directory*, which defaults to ``False``. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2065 | |
Georg Brandl | 64a41ed | 2010-10-06 08:52:48 +0000 | [diff] [blame] | 2066 | On Windows, a symlink represents a file or a directory, and does not morph to |
| 2067 | the target dynamically. For this reason, when creating a symlink on Windows, |
| 2068 | if the target is not already present, the symlink will default to being a |
| 2069 | file symlink. If *target_is_directory* is set to ``True``, the symlink will |
| 2070 | be created as a directory symlink. This parameter is ignored if the target |
| 2071 | exists (and the symlink is created with the same type as the target). |
Brian Curtin | d40e6f7 | 2010-07-08 21:39:08 +0000 | [diff] [blame] | 2072 | |
Georg Brandl | 64a41ed | 2010-10-06 08:52:48 +0000 | [diff] [blame] | 2073 | Symbolic link support was introduced in Windows 6.0 (Vista). :func:`symlink` |
| 2074 | will raise a :exc:`NotImplementedError` on Windows versions earlier than 6.0. |
Brian Curtin | 52173d4 | 2010-12-02 18:29:18 +0000 | [diff] [blame] | 2075 | |
| 2076 | .. note:: |
| 2077 | |
Brian Curtin | 9624559 | 2010-12-28 17:08:22 +0000 | [diff] [blame] | 2078 | The *SeCreateSymbolicLinkPrivilege* is required in order to successfully |
| 2079 | create symlinks. This privilege is not typically granted to regular |
| 2080 | users but is available to accounts which can escalate privileges to the |
| 2081 | administrator level. Either obtaining the privilege or running your |
| 2082 | application as an administrator are ways to successfully create symlinks. |
| 2083 | |
| 2084 | |
| 2085 | :exc:`OSError` is raised when the function is called by an unprivileged |
| 2086 | user. |
Brian Curtin | d40e6f7 | 2010-07-08 21:39:08 +0000 | [diff] [blame] | 2087 | |
Georg Brandl | 64a41ed | 2010-10-06 08:52:48 +0000 | [diff] [blame] | 2088 | Availability: Unix, Windows. |
Brian Curtin | c739569 | 2010-07-09 15:15:09 +0000 | [diff] [blame] | 2089 | |
Georg Brandl | b382337 | 2010-07-10 08:58:37 +0000 | [diff] [blame] | 2090 | .. versionchanged:: 3.2 |
| 2091 | Added support for Windows 6.0 (Vista) symbolic links. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2092 | |
| 2093 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 2094 | .. function:: sync() |
| 2095 | |
| 2096 | Force write of everything to disk. |
| 2097 | |
| 2098 | Availability: Unix. |
| 2099 | |
| 2100 | .. versionadded:: 3.3 |
| 2101 | |
| 2102 | |
| 2103 | .. function:: truncate(path, length) |
| 2104 | |
| 2105 | Truncate the file corresponding to *path*, so that it is at most |
| 2106 | *length* bytes in size. |
| 2107 | |
| 2108 | Availability: Unix. |
| 2109 | |
| 2110 | .. versionadded:: 3.3 |
| 2111 | |
| 2112 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2113 | .. function:: unlink(path) |
| 2114 | |
Georg Brandl | a6053b4 | 2009-09-01 08:11:14 +0000 | [diff] [blame] | 2115 | Remove (delete) the file *path*. This is the same function as |
| 2116 | :func:`remove`; the :func:`unlink` name is its traditional Unix |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2117 | name. |
| 2118 | |
| 2119 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2120 | |
| 2121 | |
| 2122 | .. function:: utime(path, times) |
| 2123 | |
Benjamin Peterson | 4cd6a95 | 2008-08-17 20:23:46 +0000 | [diff] [blame] | 2124 | Set the access and modified times of the file specified by *path*. If *times* |
| 2125 | is ``None``, then the file's access and modified times are set to the current |
| 2126 | time. (The effect is similar to running the Unix program :program:`touch` on |
| 2127 | the path.) Otherwise, *times* must be a 2-tuple of numbers, of the form |
| 2128 | ``(atime, mtime)`` which is used to set the access and modified times, |
| 2129 | respectively. Whether a directory can be given for *path* depends on whether |
| 2130 | the operating system implements directories as files (for example, Windows |
| 2131 | does not). Note that the exact times you set here may not be returned by a |
R. David Murray | 7b1aae9 | 2011-01-24 19:34:58 +0000 | [diff] [blame] | 2132 | subsequent :func:`~os.stat` call, depending on the resolution with which your |
| 2133 | operating system records access and modification times; see :func:`~os.stat`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2134 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2135 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2136 | |
| 2137 | |
Georg Brandl | 1824415 | 2009-09-02 20:34:52 +0000 | [diff] [blame] | 2138 | .. function:: walk(top, topdown=True, onerror=None, followlinks=False) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2139 | |
| 2140 | .. index:: |
| 2141 | single: directory; walking |
| 2142 | single: directory; traversal |
| 2143 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2144 | Generate the file names in a directory tree by walking the tree |
| 2145 | either top-down or bottom-up. For each directory in the tree rooted at directory |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2146 | *top* (including *top* itself), it yields a 3-tuple ``(dirpath, dirnames, |
| 2147 | filenames)``. |
| 2148 | |
| 2149 | *dirpath* is a string, the path to the directory. *dirnames* is a list of the |
| 2150 | names of the subdirectories in *dirpath* (excluding ``'.'`` and ``'..'``). |
| 2151 | *filenames* is a list of the names of the non-directory files in *dirpath*. |
| 2152 | Note that the names in the lists contain no path components. To get a full path |
| 2153 | (which begins with *top*) to a file or directory in *dirpath*, do |
| 2154 | ``os.path.join(dirpath, name)``. |
| 2155 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2156 | If optional argument *topdown* is ``True`` or not specified, the triple for a |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2157 | directory is generated before the triples for any of its subdirectories |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2158 | (directories are generated top-down). If *topdown* is ``False``, the triple for a |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2159 | directory is generated after the triples for all of its subdirectories |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2160 | (directories are generated bottom-up). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2161 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2162 | When *topdown* is ``True``, the caller can modify the *dirnames* list in-place |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2163 | (perhaps using :keyword:`del` or slice assignment), and :func:`walk` will only |
| 2164 | recurse into the subdirectories whose names remain in *dirnames*; this can be |
| 2165 | used to prune the search, impose a specific order of visiting, or even to inform |
| 2166 | :func:`walk` about directories the caller creates or renames before it resumes |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2167 | :func:`walk` again. Modifying *dirnames* when *topdown* is ``False`` is |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2168 | ineffective, because in bottom-up mode the directories in *dirnames* are |
| 2169 | generated before *dirpath* itself is generated. |
| 2170 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2171 | By default errors from the :func:`listdir` call are ignored. If optional |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2172 | argument *onerror* is specified, it should be a function; it will be called with |
| 2173 | one argument, an :exc:`OSError` instance. It can report the error to continue |
| 2174 | with the walk, or raise the exception to abort the walk. Note that the filename |
| 2175 | is available as the ``filename`` attribute of the exception object. |
| 2176 | |
| 2177 | By default, :func:`walk` will not walk down into symbolic links that resolve to |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2178 | directories. Set *followlinks* to ``True`` to visit directories pointed to by |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2179 | symlinks, on systems that support them. |
| 2180 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2181 | .. note:: |
| 2182 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2183 | Be aware that setting *followlinks* to ``True`` can lead to infinite recursion if a |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2184 | link points to a parent directory of itself. :func:`walk` does not keep track of |
| 2185 | the directories it visited already. |
| 2186 | |
| 2187 | .. note:: |
| 2188 | |
| 2189 | If you pass a relative pathname, don't change the current working directory |
| 2190 | between resumptions of :func:`walk`. :func:`walk` never changes the current |
| 2191 | directory, and assumes that its caller doesn't either. |
| 2192 | |
| 2193 | This example displays the number of bytes taken by non-directory files in each |
| 2194 | directory under the starting directory, except that it doesn't look under any |
| 2195 | CVS subdirectory:: |
| 2196 | |
| 2197 | import os |
| 2198 | from os.path import join, getsize |
| 2199 | for root, dirs, files in os.walk('python/Lib/email'): |
Georg Brandl | 6911e3c | 2007-09-04 07:15:32 +0000 | [diff] [blame] | 2200 | print(root, "consumes", end=" ") |
| 2201 | print(sum(getsize(join(root, name)) for name in files), end=" ") |
| 2202 | print("bytes in", len(files), "non-directory files") |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2203 | if 'CVS' in dirs: |
| 2204 | dirs.remove('CVS') # don't visit CVS directories |
| 2205 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2206 | In the next example, walking the tree bottom-up is essential: :func:`rmdir` |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2207 | doesn't allow deleting a directory before the directory is empty:: |
| 2208 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2209 | # Delete everything reachable from the directory named in "top", |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2210 | # assuming there are no symbolic links. |
| 2211 | # CAUTION: This is dangerous! For example, if top == '/', it |
| 2212 | # could delete all your disk files. |
| 2213 | import os |
| 2214 | for root, dirs, files in os.walk(top, topdown=False): |
| 2215 | for name in files: |
| 2216 | os.remove(os.path.join(root, name)) |
| 2217 | for name in dirs: |
| 2218 | os.rmdir(os.path.join(root, name)) |
| 2219 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2220 | |
| 2221 | .. _os-process: |
| 2222 | |
| 2223 | Process Management |
| 2224 | ------------------ |
| 2225 | |
| 2226 | These functions may be used to create and manage processes. |
| 2227 | |
| 2228 | The various :func:`exec\*` functions take a list of arguments for the new |
| 2229 | program loaded into the process. In each case, the first of these arguments is |
| 2230 | passed to the new program as its own name rather than as an argument a user may |
| 2231 | have typed on a command line. For the C programmer, this is the ``argv[0]`` |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 2232 | passed to a program's :c:func:`main`. For example, ``os.execv('/bin/echo', |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2233 | ['foo', 'bar'])`` will only print ``bar`` on standard output; ``foo`` will seem |
| 2234 | to be ignored. |
| 2235 | |
| 2236 | |
| 2237 | .. function:: abort() |
| 2238 | |
| 2239 | Generate a :const:`SIGABRT` signal to the current process. On Unix, the default |
| 2240 | behavior is to produce a core dump; on Windows, the process immediately returns |
Victor Stinner | 6e2e3b9 | 2011-07-08 02:26:39 +0200 | [diff] [blame] | 2241 | an exit code of ``3``. Be aware that calling this function will not call the |
| 2242 | Python signal handler registered for :const:`SIGABRT` with |
| 2243 | :func:`signal.signal`. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2244 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2245 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2246 | |
| 2247 | |
| 2248 | .. function:: execl(path, arg0, arg1, ...) |
| 2249 | execle(path, arg0, arg1, ..., env) |
| 2250 | execlp(file, arg0, arg1, ...) |
| 2251 | execlpe(file, arg0, arg1, ..., env) |
| 2252 | execv(path, args) |
| 2253 | execve(path, args, env) |
| 2254 | execvp(file, args) |
| 2255 | execvpe(file, args, env) |
| 2256 | |
| 2257 | These functions all execute a new program, replacing the current process; they |
| 2258 | do not return. On Unix, the new executable is loaded into the current process, |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2259 | and will have the same process id as the caller. Errors will be reported as |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 2260 | :exc:`OSError` exceptions. |
Benjamin Peterson | e9bbc8b | 2008-09-28 02:06:32 +0000 | [diff] [blame] | 2261 | |
| 2262 | The current process is replaced immediately. Open file objects and |
| 2263 | descriptors are not flushed, so if there may be data buffered |
| 2264 | on these open files, you should flush them using |
| 2265 | :func:`sys.stdout.flush` or :func:`os.fsync` before calling an |
| 2266 | :func:`exec\*` function. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2267 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2268 | The "l" and "v" variants of the :func:`exec\*` functions differ in how |
| 2269 | command-line arguments are passed. The "l" variants are perhaps the easiest |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2270 | to work with if the number of parameters is fixed when the code is written; the |
| 2271 | individual parameters simply become additional parameters to the :func:`execl\*` |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2272 | functions. The "v" variants are good when the number of parameters is |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2273 | variable, with the arguments being passed in a list or tuple as the *args* |
| 2274 | parameter. In either case, the arguments to the child process should start with |
| 2275 | the name of the command being run, but this is not enforced. |
| 2276 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2277 | The variants which include a "p" near the end (:func:`execlp`, |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2278 | :func:`execlpe`, :func:`execvp`, and :func:`execvpe`) will use the |
| 2279 | :envvar:`PATH` environment variable to locate the program *file*. When the |
| 2280 | environment is being replaced (using one of the :func:`exec\*e` variants, |
| 2281 | discussed in the next paragraph), the new environment is used as the source of |
| 2282 | the :envvar:`PATH` variable. The other variants, :func:`execl`, :func:`execle`, |
| 2283 | :func:`execv`, and :func:`execve`, will not use the :envvar:`PATH` variable to |
| 2284 | locate the executable; *path* must contain an appropriate absolute or relative |
| 2285 | path. |
| 2286 | |
| 2287 | For :func:`execle`, :func:`execlpe`, :func:`execve`, and :func:`execvpe` (note |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2288 | that these all end in "e"), the *env* parameter must be a mapping which is |
Christian Heimes | a342c01 | 2008-04-20 21:01:16 +0000 | [diff] [blame] | 2289 | used to define the environment variables for the new process (these are used |
| 2290 | instead of the current process' environment); the functions :func:`execl`, |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2291 | :func:`execlp`, :func:`execv`, and :func:`execvp` all cause the new process to |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 2292 | inherit the environment of the current process. |
Benjamin Peterson | e9bbc8b | 2008-09-28 02:06:32 +0000 | [diff] [blame] | 2293 | |
| 2294 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2295 | |
| 2296 | |
| 2297 | .. function:: _exit(n) |
| 2298 | |
Georg Brandl | 6f4e68d | 2010-10-17 10:51:45 +0000 | [diff] [blame] | 2299 | Exit the process with status *n*, without calling cleanup handlers, flushing |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2300 | stdio buffers, etc. |
| 2301 | |
| 2302 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2303 | |
| 2304 | .. note:: |
| 2305 | |
Georg Brandl | 6f4e68d | 2010-10-17 10:51:45 +0000 | [diff] [blame] | 2306 | The standard way to exit is ``sys.exit(n)``. :func:`_exit` should |
| 2307 | normally only be used in the child process after a :func:`fork`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2308 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2309 | The following exit codes are defined and can be used with :func:`_exit`, |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2310 | although they are not required. These are typically used for system programs |
| 2311 | written in Python, such as a mail server's external command delivery program. |
| 2312 | |
| 2313 | .. note:: |
| 2314 | |
| 2315 | Some of these may not be available on all Unix platforms, since there is some |
| 2316 | variation. These constants are defined where they are defined by the underlying |
| 2317 | platform. |
| 2318 | |
| 2319 | |
| 2320 | .. data:: EX_OK |
| 2321 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2322 | Exit code that means no error occurred. |
| 2323 | |
| 2324 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2325 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2326 | |
| 2327 | .. data:: EX_USAGE |
| 2328 | |
| 2329 | Exit code that means the command was used incorrectly, such as when the wrong |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2330 | number of arguments are given. |
| 2331 | |
| 2332 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2333 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2334 | |
| 2335 | .. data:: EX_DATAERR |
| 2336 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2337 | Exit code that means the input data was incorrect. |
| 2338 | |
| 2339 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2340 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2341 | |
| 2342 | .. data:: EX_NOINPUT |
| 2343 | |
| 2344 | Exit code that means an input file did not exist or was not readable. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2345 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2346 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2347 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2348 | |
| 2349 | .. data:: EX_NOUSER |
| 2350 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2351 | Exit code that means a specified user did not exist. |
| 2352 | |
| 2353 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2354 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2355 | |
| 2356 | .. data:: EX_NOHOST |
| 2357 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2358 | Exit code that means a specified host did not exist. |
| 2359 | |
| 2360 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2361 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2362 | |
| 2363 | .. data:: EX_UNAVAILABLE |
| 2364 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2365 | Exit code that means that a required service is unavailable. |
| 2366 | |
| 2367 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2368 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2369 | |
| 2370 | .. data:: EX_SOFTWARE |
| 2371 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2372 | Exit code that means an internal software error was detected. |
| 2373 | |
| 2374 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2375 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2376 | |
| 2377 | .. data:: EX_OSERR |
| 2378 | |
| 2379 | Exit code that means an operating system error was detected, such as the |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2380 | inability to fork or create a pipe. |
| 2381 | |
| 2382 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2383 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2384 | |
| 2385 | .. data:: EX_OSFILE |
| 2386 | |
| 2387 | Exit code that means some system file did not exist, could not be opened, or had |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2388 | some other kind of error. |
| 2389 | |
| 2390 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2391 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2392 | |
| 2393 | .. data:: EX_CANTCREAT |
| 2394 | |
| 2395 | Exit code that means a user specified output file could not be created. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2396 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2397 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2398 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2399 | |
| 2400 | .. data:: EX_IOERR |
| 2401 | |
| 2402 | Exit code that means that an error occurred while doing I/O on some file. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2403 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2404 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2405 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2406 | |
| 2407 | .. data:: EX_TEMPFAIL |
| 2408 | |
| 2409 | Exit code that means a temporary failure occurred. This indicates something |
| 2410 | that may not really be an error, such as a network connection that couldn't be |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2411 | made during a retryable operation. |
| 2412 | |
| 2413 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2414 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2415 | |
| 2416 | .. data:: EX_PROTOCOL |
| 2417 | |
| 2418 | Exit code that means that a protocol exchange was illegal, invalid, or not |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2419 | understood. |
| 2420 | |
| 2421 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2422 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2423 | |
| 2424 | .. data:: EX_NOPERM |
| 2425 | |
| 2426 | Exit code that means that there were insufficient permissions to perform the |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2427 | operation (but not intended for file system problems). |
| 2428 | |
| 2429 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2430 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2431 | |
| 2432 | .. data:: EX_CONFIG |
| 2433 | |
| 2434 | Exit code that means that some kind of configuration error occurred. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2435 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2436 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2437 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2438 | |
| 2439 | .. data:: EX_NOTFOUND |
| 2440 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2441 | Exit code that means something like "an entry was not found". |
| 2442 | |
| 2443 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2444 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2445 | |
| 2446 | .. function:: fork() |
| 2447 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2448 | Fork a child process. Return ``0`` in the child and the child's process id in the |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 2449 | parent. If an error occurs :exc:`OSError` is raised. |
Benjamin Peterson | bcd8ac3 | 2008-10-10 22:20:52 +0000 | [diff] [blame] | 2450 | |
| 2451 | Note that some platforms including FreeBSD <= 6.3, Cygwin and OS/2 EMX have |
| 2452 | known issues when using fork() from a thread. |
| 2453 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2454 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2455 | |
| 2456 | |
| 2457 | .. function:: forkpty() |
| 2458 | |
| 2459 | Fork a child process, using a new pseudo-terminal as the child's controlling |
| 2460 | terminal. Return a pair of ``(pid, fd)``, where *pid* is ``0`` in the child, the |
| 2461 | new child's process id in the parent, and *fd* is the file descriptor of the |
| 2462 | master end of the pseudo-terminal. For a more portable approach, use the |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 2463 | :mod:`pty` module. If an error occurs :exc:`OSError` is raised. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2464 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2465 | Availability: some flavors of Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2466 | |
| 2467 | |
| 2468 | .. function:: kill(pid, sig) |
| 2469 | |
| 2470 | .. index:: |
| 2471 | single: process; killing |
| 2472 | single: process; signalling |
| 2473 | |
| 2474 | Send signal *sig* to the process *pid*. Constants for the specific signals |
| 2475 | available on the host platform are defined in the :mod:`signal` module. |
Brian Curtin | eb24d74 | 2010-04-12 17:16:38 +0000 | [diff] [blame] | 2476 | |
| 2477 | Windows: The :data:`signal.CTRL_C_EVENT` and |
| 2478 | :data:`signal.CTRL_BREAK_EVENT` signals are special signals which can |
| 2479 | only be sent to console processes which share a common console window, |
| 2480 | e.g., some subprocesses. Any other value for *sig* will cause the process |
| 2481 | to be unconditionally killed by the TerminateProcess API, and the exit code |
| 2482 | will be set to *sig*. The Windows version of :func:`kill` additionally takes |
| 2483 | process handles to be killed. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2484 | |
Victor Stinner | b3e7219 | 2011-05-08 01:46:11 +0200 | [diff] [blame] | 2485 | See also :func:`signal.pthread_kill`. |
| 2486 | |
Georg Brandl | 67b21b7 | 2010-08-17 15:07:14 +0000 | [diff] [blame] | 2487 | .. versionadded:: 3.2 |
| 2488 | Windows support. |
Brian Curtin | 904bd39 | 2010-04-20 15:28:06 +0000 | [diff] [blame] | 2489 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2490 | |
| 2491 | .. function:: killpg(pgid, sig) |
| 2492 | |
| 2493 | .. index:: |
| 2494 | single: process; killing |
| 2495 | single: process; signalling |
| 2496 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2497 | Send the signal *sig* to the process group *pgid*. |
| 2498 | |
| 2499 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2500 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2501 | |
| 2502 | .. function:: nice(increment) |
| 2503 | |
| 2504 | Add *increment* to the process's "niceness". Return the new niceness. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2505 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2506 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2507 | |
| 2508 | |
| 2509 | .. function:: plock(op) |
| 2510 | |
| 2511 | Lock program segments into memory. The value of *op* (defined in |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2512 | ``<sys/lock.h>``) determines which segments are locked. |
| 2513 | |
| 2514 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2515 | |
| 2516 | |
| 2517 | .. function:: popen(...) |
| 2518 | :noindex: |
| 2519 | |
| 2520 | Run child processes, returning opened pipes for communications. These functions |
| 2521 | are described in section :ref:`os-newstreams`. |
| 2522 | |
| 2523 | |
| 2524 | .. function:: spawnl(mode, path, ...) |
| 2525 | spawnle(mode, path, ..., env) |
| 2526 | spawnlp(mode, file, ...) |
| 2527 | spawnlpe(mode, file, ..., env) |
| 2528 | spawnv(mode, path, args) |
| 2529 | spawnve(mode, path, args, env) |
| 2530 | spawnvp(mode, file, args) |
| 2531 | spawnvpe(mode, file, args, env) |
| 2532 | |
| 2533 | Execute the program *path* in a new process. |
| 2534 | |
| 2535 | (Note that the :mod:`subprocess` module provides more powerful facilities for |
| 2536 | spawning new processes and retrieving their results; using that module is |
Benjamin Peterson | 87c8d87 | 2009-06-11 22:54:11 +0000 | [diff] [blame] | 2537 | preferable to using these functions. Check especially the |
| 2538 | :ref:`subprocess-replacements` section.) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2539 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2540 | If *mode* is :const:`P_NOWAIT`, this function returns the process id of the new |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2541 | process; if *mode* is :const:`P_WAIT`, returns the process's exit code if it |
| 2542 | exits normally, or ``-signal``, where *signal* is the signal that killed the |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2543 | process. On Windows, the process id will actually be the process handle, so can |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2544 | be used with the :func:`waitpid` function. |
| 2545 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2546 | The "l" and "v" variants of the :func:`spawn\*` functions differ in how |
| 2547 | command-line arguments are passed. The "l" variants are perhaps the easiest |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2548 | to work with if the number of parameters is fixed when the code is written; the |
| 2549 | individual parameters simply become additional parameters to the |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2550 | :func:`spawnl\*` functions. The "v" variants are good when the number of |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2551 | parameters is variable, with the arguments being passed in a list or tuple as |
| 2552 | the *args* parameter. In either case, the arguments to the child process must |
| 2553 | start with the name of the command being run. |
| 2554 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2555 | The variants which include a second "p" near the end (:func:`spawnlp`, |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2556 | :func:`spawnlpe`, :func:`spawnvp`, and :func:`spawnvpe`) will use the |
| 2557 | :envvar:`PATH` environment variable to locate the program *file*. When the |
| 2558 | environment is being replaced (using one of the :func:`spawn\*e` variants, |
| 2559 | discussed in the next paragraph), the new environment is used as the source of |
| 2560 | the :envvar:`PATH` variable. The other variants, :func:`spawnl`, |
| 2561 | :func:`spawnle`, :func:`spawnv`, and :func:`spawnve`, will not use the |
| 2562 | :envvar:`PATH` variable to locate the executable; *path* must contain an |
| 2563 | appropriate absolute or relative path. |
| 2564 | |
| 2565 | For :func:`spawnle`, :func:`spawnlpe`, :func:`spawnve`, and :func:`spawnvpe` |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2566 | (note that these all end in "e"), the *env* parameter must be a mapping |
Christian Heimes | a342c01 | 2008-04-20 21:01:16 +0000 | [diff] [blame] | 2567 | which is used to define the environment variables for the new process (they are |
| 2568 | used instead of the current process' environment); the functions |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2569 | :func:`spawnl`, :func:`spawnlp`, :func:`spawnv`, and :func:`spawnvp` all cause |
Benjamin Peterson | d23f822 | 2009-04-05 19:13:16 +0000 | [diff] [blame] | 2570 | the new process to inherit the environment of the current process. Note that |
| 2571 | keys and values in the *env* dictionary must be strings; invalid keys or |
| 2572 | values will cause the function to fail, with a return value of ``127``. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2573 | |
| 2574 | As an example, the following calls to :func:`spawnlp` and :func:`spawnvpe` are |
| 2575 | equivalent:: |
| 2576 | |
| 2577 | import os |
| 2578 | os.spawnlp(os.P_WAIT, 'cp', 'cp', 'index.html', '/dev/null') |
| 2579 | |
| 2580 | L = ['cp', 'index.html', '/dev/null'] |
| 2581 | os.spawnvpe(os.P_WAIT, 'cp', L, os.environ) |
| 2582 | |
| 2583 | Availability: Unix, Windows. :func:`spawnlp`, :func:`spawnlpe`, :func:`spawnvp` |
Antoine Pitrou | 0e752dd | 2011-07-19 01:26:58 +0200 | [diff] [blame] | 2584 | and :func:`spawnvpe` are not available on Windows. :func:`spawnle` and |
| 2585 | :func:`spawnve` are not thread-safe on Windows; we advise you to use the |
| 2586 | :mod:`subprocess` module instead. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2587 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2588 | |
| 2589 | .. data:: P_NOWAIT |
| 2590 | P_NOWAITO |
| 2591 | |
| 2592 | Possible values for the *mode* parameter to the :func:`spawn\*` family of |
| 2593 | functions. If either of these values is given, the :func:`spawn\*` functions |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2594 | will return as soon as the new process has been created, with the process id as |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2595 | the return value. |
| 2596 | |
| 2597 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2598 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2599 | |
| 2600 | .. data:: P_WAIT |
| 2601 | |
| 2602 | Possible value for the *mode* parameter to the :func:`spawn\*` family of |
| 2603 | functions. If this is given as *mode*, the :func:`spawn\*` functions will not |
| 2604 | return until the new process has run to completion and will return the exit code |
| 2605 | of the process the run is successful, or ``-signal`` if a signal kills the |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2606 | process. |
| 2607 | |
| 2608 | Availability: Unix, Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2609 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2610 | |
| 2611 | .. data:: P_DETACH |
| 2612 | P_OVERLAY |
| 2613 | |
| 2614 | Possible values for the *mode* parameter to the :func:`spawn\*` family of |
| 2615 | functions. These are less portable than those listed above. :const:`P_DETACH` |
| 2616 | is similar to :const:`P_NOWAIT`, but the new process is detached from the |
| 2617 | console of the calling process. If :const:`P_OVERLAY` is used, the current |
| 2618 | process will be replaced; the :func:`spawn\*` function will not return. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2619 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2620 | Availability: Windows. |
| 2621 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2622 | |
| 2623 | .. function:: startfile(path[, operation]) |
| 2624 | |
| 2625 | Start a file with its associated application. |
| 2626 | |
| 2627 | When *operation* is not specified or ``'open'``, this acts like double-clicking |
| 2628 | the file in Windows Explorer, or giving the file name as an argument to the |
| 2629 | :program:`start` command from the interactive command shell: the file is opened |
| 2630 | with whatever application (if any) its extension is associated. |
| 2631 | |
| 2632 | When another *operation* is given, it must be a "command verb" that specifies |
| 2633 | what should be done with the file. Common verbs documented by Microsoft are |
| 2634 | ``'print'`` and ``'edit'`` (to be used on files) as well as ``'explore'`` and |
| 2635 | ``'find'`` (to be used on directories). |
| 2636 | |
| 2637 | :func:`startfile` returns as soon as the associated application is launched. |
| 2638 | There is no option to wait for the application to close, and no way to retrieve |
| 2639 | the application's exit status. The *path* parameter is relative to the current |
| 2640 | directory. If you want to use an absolute path, make sure the first character |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 2641 | is not a slash (``'/'``); the underlying Win32 :c:func:`ShellExecute` function |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2642 | doesn't work if it is. Use the :func:`os.path.normpath` function to ensure that |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2643 | the path is properly encoded for Win32. |
| 2644 | |
| 2645 | Availability: Windows. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2646 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2647 | |
| 2648 | .. function:: system(command) |
| 2649 | |
| 2650 | Execute the command (a string) in a subshell. This is implemented by calling |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 2651 | the Standard C function :c:func:`system`, and has the same limitations. |
Georg Brandl | 8f7b427 | 2010-10-14 06:35:53 +0000 | [diff] [blame] | 2652 | Changes to :data:`sys.stdin`, etc. are not reflected in the environment of |
| 2653 | the executed command. If *command* generates any output, it will be sent to |
| 2654 | the interpreter standard output stream. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2655 | |
| 2656 | On Unix, the return value is the exit status of the process encoded in the |
Georg Brandl | 8f7b427 | 2010-10-14 06:35:53 +0000 | [diff] [blame] | 2657 | format specified for :func:`wait`. Note that POSIX does not specify the |
| 2658 | meaning of the return value of the C :c:func:`system` function, so the return |
| 2659 | value of the Python function is system-dependent. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2660 | |
Georg Brandl | 8f7b427 | 2010-10-14 06:35:53 +0000 | [diff] [blame] | 2661 | On Windows, the return value is that returned by the system shell after |
| 2662 | running *command*. The shell is given by the Windows environment variable |
| 2663 | :envvar:`COMSPEC`: it is usually :program:`cmd.exe`, which returns the exit |
| 2664 | status of the command run; on systems using a non-native shell, consult your |
| 2665 | shell documentation. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2666 | |
Georg Brandl | 8f7b427 | 2010-10-14 06:35:53 +0000 | [diff] [blame] | 2667 | The :mod:`subprocess` module provides more powerful facilities for spawning |
| 2668 | new processes and retrieving their results; using that module is preferable |
| 2669 | to using this function. See the :ref:`subprocess-replacements` section in |
| 2670 | the :mod:`subprocess` documentation for some helpful recipes. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2671 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2672 | Availability: Unix, Windows. |
| 2673 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2674 | |
| 2675 | .. function:: times() |
| 2676 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2677 | Return a 5-tuple of floating point numbers indicating accumulated (processor |
| 2678 | or other) times, in seconds. The items are: user time, system time, |
| 2679 | children's user time, children's system time, and elapsed real time since a |
| 2680 | fixed point in the past, in that order. See the Unix manual page |
| 2681 | :manpage:`times(2)` or the corresponding Windows Platform API documentation. |
| 2682 | On Windows, only the first two items are filled, the others are zero. |
| 2683 | |
| 2684 | Availability: Unix, Windows |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2685 | |
| 2686 | |
| 2687 | .. function:: wait() |
| 2688 | |
| 2689 | Wait for completion of a child process, and return a tuple containing its pid |
| 2690 | and exit status indication: a 16-bit number, whose low byte is the signal number |
| 2691 | that killed the process, and whose high byte is the exit status (if the signal |
| 2692 | number is zero); the high bit of the low byte is set if a core file was |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2693 | produced. |
| 2694 | |
| 2695 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2696 | |
Ross Lagerwall | 7807c35 | 2011-03-17 20:20:30 +0200 | [diff] [blame] | 2697 | .. function:: waitid(idtype, id, options) |
| 2698 | |
| 2699 | Wait for the completion of one or more child processes. |
| 2700 | *idtype* can be :data:`P_PID`, :data:`P_PGID` or :data:`P_ALL`. |
| 2701 | *id* specifies the pid to wait on. |
| 2702 | *options* is constructed from the ORing of one or more of :data:`WEXITED`, |
| 2703 | :data:`WSTOPPED` or :data:`WCONTINUED` and additionally may be ORed with |
| 2704 | :data:`WNOHANG` or :data:`WNOWAIT`. The return value is an object |
| 2705 | representing the data contained in the :c:type:`siginfo_t` structure, namely: |
| 2706 | :attr:`si_pid`, :attr:`si_uid`, :attr:`si_signo`, :attr:`si_status`, |
| 2707 | :attr:`si_code` or ``None`` if :data:`WNOHANG` is specified and there are no |
| 2708 | children in a waitable state. |
| 2709 | |
| 2710 | Availability: Unix. |
| 2711 | |
| 2712 | .. versionadded:: 3.3 |
| 2713 | |
| 2714 | .. data:: P_PID |
| 2715 | P_PGID |
| 2716 | P_ALL |
| 2717 | |
| 2718 | These are the possible values for *idtype* in :func:`waitid`. They affect |
| 2719 | how *id* is interpreted. |
| 2720 | |
| 2721 | Availability: Unix. |
| 2722 | |
| 2723 | .. versionadded:: 3.3 |
| 2724 | |
| 2725 | .. data:: WEXITED |
| 2726 | WSTOPPED |
| 2727 | WNOWAIT |
| 2728 | |
| 2729 | Flags that can be used in *options* in :func:`waitid` that specify what |
| 2730 | child signal to wait for. |
| 2731 | |
| 2732 | Availability: Unix. |
| 2733 | |
| 2734 | .. versionadded:: 3.3 |
| 2735 | |
| 2736 | |
| 2737 | .. data:: CLD_EXITED |
| 2738 | CLD_DUMPED |
| 2739 | CLD_TRAPPED |
| 2740 | CLD_CONTINUED |
| 2741 | |
| 2742 | These are the possible values for :attr:`si_code` in the result returned by |
| 2743 | :func:`waitid`. |
| 2744 | |
| 2745 | Availability: Unix. |
| 2746 | |
| 2747 | .. versionadded:: 3.3 |
| 2748 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2749 | |
| 2750 | .. function:: waitpid(pid, options) |
| 2751 | |
| 2752 | The details of this function differ on Unix and Windows. |
| 2753 | |
| 2754 | On Unix: Wait for completion of a child process given by process id *pid*, and |
| 2755 | return a tuple containing its process id and exit status indication (encoded as |
| 2756 | for :func:`wait`). The semantics of the call are affected by the value of the |
| 2757 | integer *options*, which should be ``0`` for normal operation. |
| 2758 | |
| 2759 | If *pid* is greater than ``0``, :func:`waitpid` requests status information for |
| 2760 | that specific process. If *pid* is ``0``, the request is for the status of any |
| 2761 | child in the process group of the current process. If *pid* is ``-1``, the |
| 2762 | request pertains to any child of the current process. If *pid* is less than |
| 2763 | ``-1``, status is requested for any process in the process group ``-pid`` (the |
| 2764 | absolute value of *pid*). |
| 2765 | |
Benjamin Peterson | 4cd6a95 | 2008-08-17 20:23:46 +0000 | [diff] [blame] | 2766 | An :exc:`OSError` is raised with the value of errno when the syscall |
| 2767 | returns -1. |
| 2768 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2769 | On Windows: Wait for completion of a process given by process handle *pid*, and |
| 2770 | return a tuple containing *pid*, and its exit status shifted left by 8 bits |
| 2771 | (shifting makes cross-platform use of the function easier). A *pid* less than or |
| 2772 | equal to ``0`` has no special meaning on Windows, and raises an exception. The |
| 2773 | value of integer *options* has no effect. *pid* can refer to any process whose |
| 2774 | id is known, not necessarily a child process. The :func:`spawn` functions called |
| 2775 | with :const:`P_NOWAIT` return suitable process handles. |
| 2776 | |
| 2777 | |
| 2778 | .. function:: wait3([options]) |
| 2779 | |
| 2780 | Similar to :func:`waitpid`, except no process id argument is given and a |
| 2781 | 3-element tuple containing the child's process id, exit status indication, and |
| 2782 | resource usage information is returned. Refer to :mod:`resource`.\ |
| 2783 | :func:`getrusage` for details on resource usage information. The option |
| 2784 | argument is the same as that provided to :func:`waitpid` and :func:`wait4`. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2785 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2786 | Availability: Unix. |
| 2787 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2788 | |
| 2789 | .. function:: wait4(pid, options) |
| 2790 | |
| 2791 | Similar to :func:`waitpid`, except a 3-element tuple, containing the child's |
| 2792 | process id, exit status indication, and resource usage information is returned. |
| 2793 | Refer to :mod:`resource`.\ :func:`getrusage` for details on resource usage |
| 2794 | information. The arguments to :func:`wait4` are the same as those provided to |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2795 | :func:`waitpid`. |
| 2796 | |
| 2797 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2798 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2799 | |
| 2800 | .. data:: WNOHANG |
| 2801 | |
| 2802 | The option for :func:`waitpid` to return immediately if no child process status |
| 2803 | is available immediately. The function returns ``(0, 0)`` in this case. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2804 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2805 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2806 | |
| 2807 | |
| 2808 | .. data:: WCONTINUED |
| 2809 | |
| 2810 | This option causes child processes to be reported if they have been continued |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2811 | from a job control stop since their status was last reported. |
| 2812 | |
| 2813 | Availability: Some Unix systems. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2814 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2815 | |
| 2816 | .. data:: WUNTRACED |
| 2817 | |
| 2818 | This option causes child processes to be reported if they have been stopped but |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2819 | their current state has not been reported since they were stopped. |
| 2820 | |
| 2821 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2822 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2823 | |
| 2824 | The following functions take a process status code as returned by |
| 2825 | :func:`system`, :func:`wait`, or :func:`waitpid` as a parameter. They may be |
| 2826 | used to determine the disposition of a process. |
| 2827 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2828 | .. function:: WCOREDUMP(status) |
| 2829 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2830 | Return ``True`` if a core dump was generated for the process, otherwise |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2831 | return ``False``. |
| 2832 | |
| 2833 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2834 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2835 | |
| 2836 | .. function:: WIFCONTINUED(status) |
| 2837 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2838 | Return ``True`` if the process has been continued from a job control stop, |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2839 | otherwise return ``False``. |
| 2840 | |
| 2841 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2842 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2843 | |
| 2844 | .. function:: WIFSTOPPED(status) |
| 2845 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2846 | Return ``True`` if the process has been stopped, otherwise return |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2847 | ``False``. |
| 2848 | |
| 2849 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2850 | |
| 2851 | |
| 2852 | .. function:: WIFSIGNALED(status) |
| 2853 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2854 | Return ``True`` if the process exited due to a signal, otherwise return |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2855 | ``False``. |
| 2856 | |
| 2857 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2858 | |
| 2859 | |
| 2860 | .. function:: WIFEXITED(status) |
| 2861 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 2862 | Return ``True`` if the process exited using the :manpage:`exit(2)` system call, |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2863 | otherwise return ``False``. |
| 2864 | |
| 2865 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2866 | |
| 2867 | |
| 2868 | .. function:: WEXITSTATUS(status) |
| 2869 | |
| 2870 | If ``WIFEXITED(status)`` is true, return the integer parameter to the |
| 2871 | :manpage:`exit(2)` system call. Otherwise, the return value is meaningless. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2872 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 2873 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2874 | |
| 2875 | |
| 2876 | .. function:: WSTOPSIG(status) |
| 2877 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2878 | Return the signal which caused the process to stop. |
| 2879 | |
| 2880 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2881 | |
| 2882 | |
| 2883 | .. function:: WTERMSIG(status) |
| 2884 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 2885 | Return the signal which caused the process to exit. |
| 2886 | |
| 2887 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 2888 | |
| 2889 | |
Benjamin Peterson | 94b580d | 2011-08-02 17:30:04 -0500 | [diff] [blame] | 2890 | Interface to the scheduler |
| 2891 | -------------------------- |
| 2892 | |
| 2893 | These functions control how a process is allocated CPU time by the operating |
| 2894 | system. They are only available on some Unix platforms. For more detailed |
| 2895 | information, consult your Unix manpages. |
| 2896 | |
| 2897 | .. versionadded:: 3.3 |
| 2898 | |
| 2899 | The following scheduling policies are exposed if they are a supported by the |
| 2900 | operating system. |
| 2901 | |
| 2902 | .. data:: SCHED_OTHER |
| 2903 | |
| 2904 | The default scheduling policy. |
| 2905 | |
| 2906 | .. data:: SCHED_BATCH |
| 2907 | |
| 2908 | Scheduling policy for CPU-intensive processes that tries to preserve |
| 2909 | interactivity on the rest of the computer. |
| 2910 | |
| 2911 | .. data:: SCHED_IDLE |
| 2912 | |
| 2913 | Scheduling policy for extremely low priority background tasks. |
| 2914 | |
| 2915 | .. data:: SCHED_SPORADIC |
| 2916 | |
| 2917 | Scheduling policy for sporadic server programs. |
| 2918 | |
| 2919 | .. data:: SCHED_FIFO |
| 2920 | |
| 2921 | A First In First Out scheduling policy. |
| 2922 | |
| 2923 | .. data:: SCHED_RR |
| 2924 | |
| 2925 | A round-robin scheduling policy. |
| 2926 | |
| 2927 | .. data:: SCHED_RESET_ON_FORK |
| 2928 | |
| 2929 | This flag can OR'ed with any other scheduling policy. When a process with |
| 2930 | this flag set forks, its child's scheduling policy and priority are reset to |
| 2931 | the default. |
| 2932 | |
| 2933 | |
| 2934 | .. class:: sched_param(sched_priority) |
| 2935 | |
| 2936 | This class represents tunable scheduling parameters used in |
| 2937 | :func:`sched_setparam`, :func:`sched_setscheduler`, and |
| 2938 | :func:`sched_getparam`. It is immutable. |
| 2939 | |
| 2940 | At the moment, there is only one possible parameter: |
| 2941 | |
| 2942 | .. attribute:: sched_priority |
| 2943 | |
| 2944 | The scheduling priority for a scheduling policy. |
| 2945 | |
| 2946 | |
| 2947 | .. function:: sched_get_priority_min(policy) |
| 2948 | |
| 2949 | Get the minimum priority value for *policy*. *policy* is one of the |
| 2950 | scheduling policy constants above. |
| 2951 | |
| 2952 | |
| 2953 | .. function:: sched_get_priority_max(policy) |
| 2954 | |
| 2955 | Get the maximum priority value for *policy*. *policy* is one of the |
| 2956 | scheduling policy constants above. |
| 2957 | |
| 2958 | |
| 2959 | .. function:: sched_setscheduler(pid, policy, param) |
| 2960 | |
| 2961 | Set the scheduling policy for the process with PID *pid*. A *pid* of 0 means |
| 2962 | the calling process. *policy* is one of the scheduling policy constants |
| 2963 | above. *param* is a :class:`sched_param` instance. |
| 2964 | |
| 2965 | |
| 2966 | .. function:: sched_getscheduler(pid) |
| 2967 | |
| 2968 | Return the scheduling policy for the process with PID *pid*. A *pid* of 0 |
| 2969 | means the calling process. The result is one of the scheduling policy |
| 2970 | constants above. |
| 2971 | |
| 2972 | |
| 2973 | .. function:: sched_setparam(pid, param) |
| 2974 | |
| 2975 | Set a scheduling parameters for the process with PID *pid*. A *pid* of 0 means |
| 2976 | the calling process. *param* is a :class:`sched_param` instance. |
| 2977 | |
| 2978 | |
| 2979 | .. function:: sched_getparam(pid) |
| 2980 | |
| 2981 | Return the scheduling parameters as a :class:`sched_param` instance for the |
| 2982 | process with PID *pid*. A *pid* of 0 means the calling process. |
| 2983 | |
| 2984 | |
| 2985 | .. function:: sched_rr_get_interval(pid) |
| 2986 | |
| 2987 | Return the round-robin quantum in seconds for the process with PID *pid*. A |
| 2988 | *pid* of 0 means the calling process. |
| 2989 | |
| 2990 | |
| 2991 | .. function:: sched_yield() |
| 2992 | |
| 2993 | Voluntarily relinquish the CPU. |
| 2994 | |
| 2995 | |
| 2996 | .. class:: cpu_set(ncpus) |
| 2997 | |
| 2998 | :class:`cpu_set` represents a set of CPUs on which a process is eligible to |
| 2999 | run. *ncpus* is the number of CPUs the set should describe. Methods on |
| 3000 | :class:`cpu_set` allow CPUs to be add or removed. |
| 3001 | |
| 3002 | :class:`cpu_set` supports the AND, OR, and XOR bitwise operations. For |
| 3003 | example, given two cpu_sets, ``one`` and ``two``, ``one | two`` returns a |
| 3004 | :class:`cpu_set` containing the cpus enabled both in ``one`` and ``two``. |
| 3005 | |
| 3006 | .. method:: set(i) |
| 3007 | |
| 3008 | Enable CPU *i*. |
| 3009 | |
| 3010 | .. method:: clear(i) |
| 3011 | |
| 3012 | Remove CPU *i*. |
| 3013 | |
| 3014 | .. method:: isset(i) |
| 3015 | |
| 3016 | Return ``True`` if CPU *i* is enabled in the set. |
| 3017 | |
| 3018 | .. method:: count() |
| 3019 | |
| 3020 | Return the number of enabled CPUs in the set. |
| 3021 | |
| 3022 | .. method:: zero() |
| 3023 | |
| 3024 | Clear the set completely. |
| 3025 | |
| 3026 | |
| 3027 | .. function:: sched_setaffinity(pid, mask) |
| 3028 | |
| 3029 | Restrict the process with PID *pid* to a set of CPUs. *mask* is a |
| 3030 | :class:`cpu_set` instance. |
| 3031 | |
| 3032 | |
| 3033 | .. function:: sched_getaffinity(pid, size) |
| 3034 | |
| 3035 | Return the :class:`cpu_set` the process with PID *pid* is restricted to. The |
| 3036 | result will contain *size* CPUs. |
| 3037 | |
| 3038 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3039 | .. _os-path: |
| 3040 | |
| 3041 | Miscellaneous System Information |
| 3042 | -------------------------------- |
| 3043 | |
| 3044 | |
| 3045 | .. function:: confstr(name) |
| 3046 | |
| 3047 | Return string-valued system configuration values. *name* specifies the |
| 3048 | configuration value to retrieve; it may be a string which is the name of a |
| 3049 | defined system value; these names are specified in a number of standards (POSIX, |
| 3050 | Unix 95, Unix 98, and others). Some platforms define additional names as well. |
| 3051 | The names known to the host operating system are given as the keys of the |
| 3052 | ``confstr_names`` dictionary. For configuration variables not included in that |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 3053 | mapping, passing an integer for *name* is also accepted. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3054 | |
| 3055 | If the configuration value specified by *name* isn't defined, ``None`` is |
| 3056 | returned. |
| 3057 | |
| 3058 | If *name* is a string and is not known, :exc:`ValueError` is raised. If a |
| 3059 | specific value for *name* is not supported by the host system, even if it is |
| 3060 | included in ``confstr_names``, an :exc:`OSError` is raised with |
| 3061 | :const:`errno.EINVAL` for the error number. |
| 3062 | |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 3063 | Availability: Unix |
| 3064 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3065 | |
| 3066 | .. data:: confstr_names |
| 3067 | |
| 3068 | Dictionary mapping names accepted by :func:`confstr` to the integer values |
| 3069 | defined for those names by the host operating system. This can be used to |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 3070 | determine the set of names known to the system. |
| 3071 | |
| 3072 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3073 | |
| 3074 | |
| 3075 | .. function:: getloadavg() |
| 3076 | |
Christian Heimes | a62da1d | 2008-01-12 19:39:10 +0000 | [diff] [blame] | 3077 | Return the number of processes in the system run queue averaged over the last |
| 3078 | 1, 5, and 15 minutes or raises :exc:`OSError` if the load average was |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 3079 | unobtainable. |
| 3080 | |
| 3081 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3082 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3083 | |
| 3084 | .. function:: sysconf(name) |
| 3085 | |
| 3086 | Return integer-valued system configuration values. If the configuration value |
| 3087 | specified by *name* isn't defined, ``-1`` is returned. The comments regarding |
| 3088 | the *name* parameter for :func:`confstr` apply here as well; the dictionary that |
| 3089 | provides information on the known names is given by ``sysconf_names``. |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 3090 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 3091 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3092 | |
| 3093 | |
| 3094 | .. data:: sysconf_names |
| 3095 | |
| 3096 | Dictionary mapping names accepted by :func:`sysconf` to the integer values |
| 3097 | defined for those names by the host operating system. This can be used to |
Benjamin Peterson | f650e46 | 2010-05-06 23:03:05 +0000 | [diff] [blame] | 3098 | determine the set of names known to the system. |
| 3099 | |
| 3100 | Availability: Unix. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3101 | |
Christian Heimes | faf2f63 | 2008-01-06 16:59:19 +0000 | [diff] [blame] | 3102 | The following data values are used to support path manipulation operations. These |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3103 | are defined for all platforms. |
| 3104 | |
| 3105 | Higher-level operations on pathnames are defined in the :mod:`os.path` module. |
| 3106 | |
| 3107 | |
| 3108 | .. data:: curdir |
| 3109 | |
| 3110 | The constant string used by the operating system to refer to the current |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 3111 | directory. This is ``'.'`` for Windows and POSIX. Also available via |
| 3112 | :mod:`os.path`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3113 | |
| 3114 | |
| 3115 | .. data:: pardir |
| 3116 | |
| 3117 | The constant string used by the operating system to refer to the parent |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 3118 | directory. This is ``'..'`` for Windows and POSIX. Also available via |
| 3119 | :mod:`os.path`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3120 | |
| 3121 | |
| 3122 | .. data:: sep |
| 3123 | |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 3124 | The character used by the operating system to separate pathname components. |
| 3125 | This is ``'/'`` for POSIX and ``'\\'`` for Windows. Note that knowing this |
| 3126 | is not sufficient to be able to parse or concatenate pathnames --- use |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3127 | :func:`os.path.split` and :func:`os.path.join` --- but it is occasionally |
| 3128 | useful. Also available via :mod:`os.path`. |
| 3129 | |
| 3130 | |
| 3131 | .. data:: altsep |
| 3132 | |
| 3133 | An alternative character used by the operating system to separate pathname |
| 3134 | components, or ``None`` if only one separator character exists. This is set to |
| 3135 | ``'/'`` on Windows systems where ``sep`` is a backslash. Also available via |
| 3136 | :mod:`os.path`. |
| 3137 | |
| 3138 | |
| 3139 | .. data:: extsep |
| 3140 | |
| 3141 | The character which separates the base filename from the extension; for example, |
| 3142 | the ``'.'`` in :file:`os.py`. Also available via :mod:`os.path`. |
| 3143 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3144 | |
| 3145 | .. data:: pathsep |
| 3146 | |
| 3147 | The character conventionally used by the operating system to separate search |
| 3148 | path components (as in :envvar:`PATH`), such as ``':'`` for POSIX or ``';'`` for |
| 3149 | Windows. Also available via :mod:`os.path`. |
| 3150 | |
| 3151 | |
| 3152 | .. data:: defpath |
| 3153 | |
| 3154 | The default search path used by :func:`exec\*p\*` and :func:`spawn\*p\*` if the |
| 3155 | environment doesn't have a ``'PATH'`` key. Also available via :mod:`os.path`. |
| 3156 | |
| 3157 | |
| 3158 | .. data:: linesep |
| 3159 | |
| 3160 | The string used to separate (or, rather, terminate) lines on the current |
Georg Brandl | c575c90 | 2008-09-13 17:46:05 +0000 | [diff] [blame] | 3161 | platform. This may be a single character, such as ``'\n'`` for POSIX, or |
| 3162 | multiple characters, for example, ``'\r\n'`` for Windows. Do not use |
| 3163 | *os.linesep* as a line terminator when writing files opened in text mode (the |
| 3164 | default); use a single ``'\n'`` instead, on all platforms. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3165 | |
| 3166 | |
| 3167 | .. data:: devnull |
| 3168 | |
Georg Brandl | 850a990 | 2010-05-21 22:04:32 +0000 | [diff] [blame] | 3169 | The file path of the null device. For example: ``'/dev/null'`` for |
| 3170 | POSIX, ``'nul'`` for Windows. Also available via :mod:`os.path`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3171 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3172 | |
| 3173 | .. _os-miscfunc: |
| 3174 | |
| 3175 | Miscellaneous Functions |
| 3176 | ----------------------- |
| 3177 | |
| 3178 | |
| 3179 | .. function:: urandom(n) |
| 3180 | |
| 3181 | Return a string of *n* random bytes suitable for cryptographic use. |
| 3182 | |
| 3183 | This function returns random bytes from an OS-specific randomness source. The |
| 3184 | returned data should be unpredictable enough for cryptographic applications, |
| 3185 | though its exact quality depends on the OS implementation. On a UNIX-like |
| 3186 | system this will query /dev/urandom, and on Windows it will use CryptGenRandom. |
| 3187 | If a randomness source is not found, :exc:`NotImplementedError` will be raised. |