8.18 commands -- Utilities for running commands
Keywords: lib

# 8.18 `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'