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1
2:mod:`commands` --- Utilities for running commands
3==================================================
4
5.. module:: commands
6   :platform: Unix
7   :synopsis: Utility functions for running external commands.
8   :deprecated:
9
10.. deprecated:: 2.6
11   The :mod:`commands` module has been removed in Python 3.  Use the
12   :mod:`subprocess` module instead.
13
14.. sectionauthor:: Sue Williams <sbw@provis.com>
15
16
17The :mod:`commands` module contains wrapper functions for :func:`os.popen` which
18take a system command as a string and return any output generated by the command
19and, optionally, the exit status.
20
21The :mod:`subprocess` module provides more powerful facilities for spawning new
22processes and retrieving their results.  Using the :mod:`subprocess` module is
23preferable to using the :mod:`commands` module.
24
25.. note::
26
27   In Python 3.x, :func:`getstatus` and two undocumented functions
28   (:func:`mk2arg` and :func:`mkarg`) have been removed.  Also,
29   :func:`getstatusoutput` and :func:`getoutput` have been moved to the
30   :mod:`subprocess` module.
31
32The :mod:`commands` module defines the following functions:
33
34
35.. function:: getstatusoutput(cmd)
36
37   Execute the string *cmd* in a shell with :func:`os.popen` and return a 2-tuple
38   ``(status, output)``.  *cmd* is actually run as ``{ cmd ; } 2>&1``, so that the
39   returned output will contain output or error messages. A trailing newline is
40   stripped from the output. The exit status for the command can be interpreted
41   according to the rules for the C function :c:func:`wait`.
42
43
44.. function:: getoutput(cmd)
45
46   Like :func:`getstatusoutput`, except the exit status is ignored and the return
47   value is a string containing the command's output.
48
49
50.. function:: getstatus(file)
51
52   Return the output of ``ls -ld file`` as a string.  This function uses the
53   :func:`getoutput` function, and properly escapes backslashes and dollar signs in
54   the argument.
55
56   .. deprecated:: 2.6
57      This function is nonobvious and useless.  The name is also misleading in the
58      presence of :func:`getstatusoutput`.
59
60
61Example::
62
63   >>> import commands
64   >>> commands.getstatusoutput('ls /bin/ls')
65   (0, '/bin/ls')
66   >>> commands.getstatusoutput('cat /bin/junk')
67   (256, 'cat: /bin/junk: No such file or directory')
68   >>> commands.getstatusoutput('/bin/junk')
69   (256, 'sh: /bin/junk: not found')
70   >>> commands.getoutput('ls /bin/ls')
71   '/bin/ls'
72   >>> commands.getstatus('/bin/ls')
73   '-rwxr-xr-x  1 root        13352 Oct 14  1994 /bin/ls'
74
75
76.. seealso::
77
78   Module :mod:`subprocess`
79      Module for spawning and managing subprocesses.
80
81