36.16. commands
— Utilities for running commands¶
2.6 版后已移除: 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.
注解
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 functionwait()
.
-
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 thegetoutput()
function, and properly escapes backslashes and dollar signs in the argument.2.6 版后已移除: 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'
参见
- Module
subprocess
Module for spawning and managing subprocesses.