| \section{Standard Module \sectcode{os}} |
| \label{module-os} |
| |
| \stmodindex{os} |
| This module provides a more portable way of using operating system |
| (OS) dependent functionality than importing an OS dependent built-in |
| module like \code{posix}. |
| |
| When the optional built-in module \code{posix} is available, this |
| module exports the same functions and data as \code{posix}; otherwise, |
| it searches for an OS dependent built-in module like \code{mac} and |
| exports the same functions and data as found there. The design of all |
| Python's built-in OS dependent modules is such that as long as the same |
| functionality is available, it uses the same interface; e.g., the |
| function \code{os.stat(\var{file})} returns stat info about a \var{file} in a |
| format compatible with the \POSIX{} interface. |
| |
| Extensions peculiar to a particular OS are also available through the |
| \code{os} module, but using them is of course a threat to portability! |
| |
| Note that after the first time \code{os} is imported, there is \emph{no} |
| performance penalty in using functions from \code{os} instead of |
| directly from the OS dependent built-in module, so there should be |
| \emph{no} reason not to use \code{os}! |
| |
| In addition to whatever the correct OS dependent module exports, the |
| following variables and functions are always exported by \code{os}: |
| |
| \setindexsubitem{(in module os)} |
| |
| \begin{datadesc}{name} |
| The name of the OS dependent module imported. The following names |
| have currently been registered: \code{'posix'}, \code{'nt'}, |
| \code{'dos'}, \code{'mac'}. |
| \end{datadesc} |
| |
| \begin{datadesc}{path} |
| The corresponding OS dependent standard module for pathname |
| operations, e.g., \code{posixpath} or \code{macpath}. Thus, (given |
| the proper imports), \code{os.path.split(\var{file})} is equivalent to but |
| more portable than \code{posixpath.split(\var{file})}. |
| \end{datadesc} |
| |
| \begin{datadesc}{curdir} |
| The constant string used by the OS to refer to the current directory, |
| e.g. \code{'.'} for \POSIX{} or \code{':'} for the Mac. |
| \end{datadesc} |
| |
| \begin{datadesc}{pardir} |
| The constant string used by the OS to refer to the parent directory, |
| e.g. \code{'..'} for \POSIX{} or \code{'::'} for the Mac. |
| \end{datadesc} |
| |
| \begin{datadesc}{sep} |
| The character used by the OS to separate pathname components, |
| e.g. \code{'/'} for \POSIX{} or \code{':'} for the Mac. Note that |
| knowing this is not sufficient to be able to parse or concatenate |
| pathnames --- better use \code{os.path.split()} and |
| \code{os.path.join()}---but it is occasionally useful. |
| \end{datadesc} |
| |
| \begin{datadesc}{altsep} |
| An alternative character used by the OS to separate pathname components, |
| or \code{None} if only one separator character exists. This is set to |
| \code{'/'} on DOS/Windows systems where \code{sep} is a backslash. |
| \end{datadesc} |
| |
| \begin{datadesc}{pathsep} |
| The character conventionally used by the OS to separate search patch |
| components (as in \code{\$PATH}), e.g.\ \code{':'} for \POSIX{} or |
| \code{';'} for MS-DOS. |
| \end{datadesc} |
| |
| \begin{datadesc}{defpath} |
| The default search path used by \code{os.exec*p*()} if the environment |
| doesn't have a \code{'PATH'} key. |
| \end{datadesc} |
| |
| \begin{funcdesc}{execl}{path\, arg0\, arg1\, ...} |
| This is equivalent to |
| \code{os.execv(\var{path}, (\var{arg0}, \var{arg1}, ...))}. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{execle}{path\, arg0\, arg1\, ...\, env} |
| This is equivalent to |
| \code{os.execve(\var{path}, (\var{arg0}, \var{arg1}, ...), \var{env})}. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{execlp}{path\, arg0\, arg1\, ...} |
| This is equivalent to |
| \code{os.execvp(\var{path}, (\var{arg0}, \var{arg1}, ...))}. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{execvp}{path\, args} |
| This is like \code{os.execv(\var{path}, \var{args})} but duplicates |
| the shell's actions in searching for an executable file in a list of |
| directories. The directory list is obtained from |
| \code{os.environ['PATH']}. |
| \end{funcdesc} |
| |
| \begin{funcdesc}{execvpe}{path\, args\, env} |
| This is a cross between \code{os.execve()} and \code{os.execvp()}. |
| The directory list is obtained from \code{\var{env}['PATH']}. |
| \end{funcdesc} |
| |
| (The functions \code{os.execv()} and \code{execve()} are not |
| documented here, since they are implemented by the OS dependent |
| module. If the OS dependent module doesn't define either of these, |
| the functions that rely on it will raise an exception. They are |
| documented in the section on module \code{posix}, together with all |
| other functions that \code{os} imports from the OS dependent module.) |