8.14 commands -- Utilities for running commands

Availability: Unix.

The commands module contains wrapper functions for os.popen() which take a system command as a string and return any output generated by the command and, optionally, the exit status.

The commands module defines the following functions:

getstatusoutput (cmd)

Execute the string cmd in a shell with os.popen() and return a 2-tuple (status, output). cmd is actually run as { cmd ; } 2>&1, so that the returned output will contain output or error messages. A trailing newline is stripped from the output. The exit status for the command can be interpreted according to the rules for the C function wait().

getoutput (cmd)

Like getstatusoutput(), except the exit status is ignored and the return value is a string containing the command's output.

getstatus (file)

Return the output of "ls -ld file" as a string. This function uses the getoutput() function, and properly escapes backslashes and dollar signs in the argument.

Example:

>>> import commands
>>> commands.getstatusoutput('ls /bin/ls')
(0, '/bin/ls')
>>> commands.getstatusoutput('cat /bin/junk')
(256, 'cat: /bin/junk: No such file or directory')
>>> commands.getstatusoutput('/bin/junk')
(256, 'sh: /bin/junk: not found')
>>> commands.getoutput('ls /bin/ls')
'/bin/ls'
>>> commands.getstatus('/bin/ls')
'-rwxr-xr-x  1 root        13352 Oct 14  1994 /bin/ls'