使用Python拆分ps的输出

在Linux上,命令ps aux输出每个stat的多列的进程列表.例如

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
...
postfix  22611  0.0  0.2  54136  2544 ?        S    15:26   0:00 pickup -l -t fifo -u
apache   22920  0.0  1.5 198340 16588 ?        S    09:58   0:05 /usr/sbin/httpd

我希望能够在使用Python时读取它,然后拆分每一行,然后拆分每一列,以便它们可以用作值.

在大多数情况下,这不是问题:

ps = subprocess.Popen(['ps', 'aux'], stdout=subprocess.PIPE).communicate()[0]
processes = ps.split('\n')

我现在可以遍历进程以获取每一行并将其拆分为空格

sep = re.compile('[\s]+')
for row in processes:
    print sep.split(row)

但是,问题是最后一列命令有时会有空格.在上面的例子中,这可以在命令中看到

pickup -l -t fifo -u

将被拆分为

['postfix', '22611', '0.0', '0.2', '54136', '2544', '?', 'S', '15:26', '0:00', 'pickup', '-l', '-t', 'fifo', '-u']

但我真的想要它:

['postfix', '22611', '0.0', '0.2', '54136', '2544', '?', 'S', '15:26', '0:00', 'pickup -l -t fifo -u']

所以我的问题是,如何拆分列,但是当涉及到命令列时,将整个字符串保留为一个列表元素而不是按空格拆分？

1> David Z..：

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使用第二个参数split指定要将字符串拆分为的最大字段数.我想你可以通过计算第一行中的字段数,即列标题来找到该数字.

ps = subprocess.Popen(['ps', 'aux'], stdout=subprocess.PIPE).communicate()[0]
processes = ps.split('\n')
# this specifies the number of splits, so the splitted lines
# will have (nfields+1) elements
nfields = len(processes[0].split()) - 1
for row in processes[1:]:
    print row.split(None, nfields)

2> 小智..：

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Check out the python.psutils package.

psutil.process_iter returns a generator which you can use to iterate over all processes. p.cmdline is a list of each Process object's cmdline arguments, separated just the way you want.

You can create a dictionary of pids vs (pid,cmdline,path) with just one line and then use it anyway you want.

pid_dict = dict([(p.pid, dict([('pid',p.pid), ('cmdline',p.cmdline), ('path',p.path)]))
                 for p in psutil.process_iter()]))

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+1,psutil绝对是要走的路(http://pypi.python.org/pypi/psutil/).它是便携式的,不依赖于ps的输出.