python - 如何从外部命令结合管道获取输出

Question

我有这样的命令。

wmctrl -lp | awk '/gedit/ { print $1 }'

我想在 python 脚本中输出它，我试过这段代码

>>> import subprocess
>>> proc =  subprocess.Popen(["wmctrl -lp", "|","awk '/gedit/ {print $1}"], shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
>>> proc.stdout.readline()
'0x0160001b -1 6504   beer-laptop x-nautilus-desktop\n'
>>> proc.stdout.readline()
'0x0352f117  0 6963   beer-laptop How to get output from external command combine with Pipe - Stack Overflow - Chromium\n'
>>> proc.stdout.readline()
'0x01400003 -1 6503   beer-laptop Bottom Expanded Edge Panel\n'
>>> 

看来我的代码是错误的，只有 wmctrl -lp 被执行了，而 | awk '{print $1}' 被省略 我期望的输出是 0x03800081

$ wmctrl -lp | awk '/gedit/ {print $1}'
0x03800081

有人帮忙吗

Answer 1

使用 shell=True 时，您应该使用单个命令行而不是数组，否则您的附加参数将被解释为 shell 参数。来自subprocess documentation :

On Unix, with shell=True: If args is a string, it specifies the command string to execute through the shell. If args is a sequence, the first item specifies the command string, and any additional items will be treated as additional shell arguments.

所以你的电话应该是:

subprocess.Popen("wmctrl -lp | sed /gedit/ '{print $1}'", shell=True, ...

我想你可能还有一个不平衡的单引号。