36.16. "commands" — Utilities for running commands
**************************************************

2.6 版後已棄用: The "commands" module has been removed in Python 3.
Use the "subprocess" module instead.

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 "subprocess" module provides more powerful facilities for spawning
new processes and retrieving their results.  Using the "subprocess"
module is preferable to using the "commands" module.

備註: In Python 3.x, "getstatus()" and two undocumented functions
  ("mk2arg()" and "mkarg()") have been removed.  Also,
  "getstatusoutput()" and "getoutput()" have been moved to the
  "subprocess" module.

The "commands" module defines the following functions:

commands.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()".

commands.getoutput(cmd)

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

commands.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.

   2.6 版後已棄用: This function is nonobvious and useless.  The name
   is also misleading in the presence of "getstatusoutput()".

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'

也參考:

  Module "subprocess"
     Module for spawning and managing subprocesses.
