Initial revision
diff --git a/Lib/commands.py b/Lib/commands.py
new file mode 100644
index 0000000..145f5db
--- /dev/null
+++ b/Lib/commands.py
@@ -0,0 +1,73 @@
+# Module 'commands'
+#
+# Various tools for executing commands and looking at their output and status.
+
+import rand
+import posix
+import path
+
+
+# Get 'ls -l' status for an object into a string
+#
+def getstatus(file):
+ return getoutput('ls -ld' + mkarg(file))
+
+
+# Get the output from a shell command into a string.
+# The exit status is ignored; a trailing newline is stripped.
+# Assume the command will work with ' >tempfile 2>&1' appended.
+# XXX This should use posix.popen() instead, should it exist.
+#
+def getoutput(cmd):
+ return getstatusoutput(cmd)[1]
+
+
+# Ditto but preserving the exit status.
+# Returns a pair (sts, output)
+#
+def getstatusoutput(cmd):
+ tmp = '/usr/tmp/wdiff' + `rand.rand()`
+ sts = -1
+ try:
+ sts = posix.system(cmd + ' >' + tmp + ' 2>&1')
+ text = readfile(tmp)
+ finally:
+ altsts = posix.system('rm -f ' + tmp)
+ if text[-1:] = '\n': text = text[:-1]
+ return sts, text
+
+
+# Return a string containing a file's contents.
+#
+def readfile(fn):
+ fp = open(fn, 'r')
+ a = ''
+ n = 8096
+ while 1:
+ b = fp.read(n)
+ if not b: break
+ a = a + b
+ return a
+
+
+# Make command argument from directory and pathname (prefix space, add quotes).
+#
+def mk2arg(head, x):
+ return mkarg(path.cat(head, x))
+
+
+# Make a shell command argument from a string.
+# Two strategies: enclose in single quotes if it contains none;
+# otherwis, enclose in double quotes and prefix quotable characters
+# with backslash.
+#
+def mkarg(x):
+ if '\'' not in x:
+ return ' \'' + x + '\''
+ s = ' "'
+ for c in x:
+ if c in '\\$"':
+ s = s + '\\'
+ s = s + c
+ s = s + '"'
+ return s