Python 运行 shell 获取输出结果的实例

> import os
> code = os.system("pwd && sleep 2")
# /User/zhipeng
> print code
# 0

> import subprocess
> subprocess.Popen("pwd && sleep 2", shell=True, cwd="/home")
# <subprocess.Popen object at 0x106498310>
# /home

> sub = subprocess.Popen("pwd && sleep 2", shell=True, stdout=subprcess.PIPE)
> sub.wait()
> print sub.stdout.read()
# /User/zhipeng

subprocess.Popen还支持一些别的参数 
bufsize,executable=None, stdin=None, stdout=None, stderr=None 
preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None 
universal_newlines=False, startupinfo=None, creationflags=0

# pip install sh
> from sh import ifconfig
> print ifconfig("eth0")

> from sh import bash
> bash("pwd")
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "/Library/Python/2.7/site-packages/sh.py", line 1021, in __call__
 return RunningCommand(cmd, call_args, stdin, stdout, stderr)
 File "/Library/Python/2.7/site-packages/sh.py", line 486, in __init__
 self.wait()
 File "/Library/Python/2.7/site-packages/sh.py", line 500, in wait
 self.handle_command_exit_code(exit_code)
 File "/Library/Python/2.7/site-packages/sh.py", line 516, in handle_command_exit_code
 raise exc(self.ran, self.process.stdout, self.process.stderr)
sh.ErrorReturnCode_126: 
 RAN: '/bin/bash ls'
 STDOUT:
 STDERR:
/bin/ls: /bin/ls: cannot execute binary file

# 不能这么用
> from sh import ls
> ls()
# hello.txt 1.txt
# ls -al
> ls(a=True, l=True)
# ls(al=True) 是不可以的

# bash -c command 可以很好的解决这个问题
# bash -c "sleep 1 && pwd"
> result = bash(c="pwd", _timeout=1, _cwd="/home")
> print result
# -rw-r--r--@ 1 zhipeng staff 0 10 13 18:30 hello.txt
# -rw-r--r--@ 1 zhipeng staff 0 10 13 18:30 1.txt

> result = bash(c="pwd", _timeout=1, _cwd="/")
> print result
# /
> bash(c="pwd && sleep 2", _timeout=1)
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "/Library/Python/2.7/site-packages/sh.py", line 1021, in __call__
 return RunningCommand(cmd, call_args, stdin, stdout, stderr)
 File "/Library/Python/2.7/site-packages/sh.py", line 486, in __init__
 self.wait()
 File "/Library/Python/2.7/site-packages/sh.py", line 498, in wait
 raise TimeoutException(-exit_code)
sh.TimeoutException

参数里面可以添加非命令参数. 需要以_开头, 例如上面的_timeout, _cwd. 详见sh.py 源码 

还支持以下参数 

internal_bufsize, err_bufsize, tee, done, in, decode_errors, tty_in, 
out, cwd, timeout_signal, bg, timeout, with, ok_code, err, env, no_out,