我想编写一个函数,该函数将执行shell命令并将其输出作为字符串返回,无论它是错误消息还是成功消息。我只想得到和用命令行得到的相同的结果。

什么样的代码示例可以做到这一点呢?

例如:

def run_command(cmd):
    # ??????

print run_command('mysqladmin create test -uroot -pmysqladmin12')
# Should output something like:
# mysqladmin: CREATE DATABASE failed; error: 'Can't create database 'test'; database exists'

当前回答

如果您需要在多个文件上运行shell命令,这对我来说很有用。

import os
import subprocess

# Define a function for running commands and capturing stdout line by line
# (Modified from Vartec's solution because it wasn't printing all lines)
def runProcess(exe):    
    p = subprocess.Popen(exe, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    return iter(p.stdout.readline, b'')

# Get all filenames in working directory
for filename in os.listdir('./'):
    # This command will be run on each file
    cmd = 'nm ' + filename

    # Run the command and capture the output line by line.
    for line in runProcess(cmd.split()):
        # Eliminate leading and trailing whitespace
        line.strip()
        # Split the output 
        output = line.split()

        # Filter the output and print relevant lines
        if len(output) > 2:
            if ((output[2] == 'set_program_name')):
                print filename
                print line

编辑:刚刚看到Max Persson的解决方案和J.F. Sebastian的建议。继续把它整合进去。

其他回答

Vartec的答案不读取所有的行,所以我做了一个版本:

def run_command(command):
    p = subprocess.Popen(command,
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT)
    return iter(p.stdout.readline, b'')

用法与公认的答案相同:

command = 'mysqladmin create test -uroot -pmysqladmin12'.split()
for line in run_command(command):
    print(line)

如果你使用subprocess python模块,你可以分别处理命令的STDOUT、STDERR和返回码。您可以看到完整命令调用器实现的示例。当然你可以用try.扩展它,除非你想。

下面的函数返回STDOUT, STDERR和Return代码,以便您可以在另一个脚本中处理它们。

import subprocess

def command_caller(command=None)
    sp = subprocess.Popen(command, stderr=subprocess.PIPE, stdout=subprocess.PIPE, shell=False)
    out, err = sp.communicate()
    if sp.returncode:
        print(
            "Return code: %(ret_code)s Error message: %(err_msg)s"
            % {"ret_code": sp.returncode, "err_msg": err}
            )
    return sp.returncode, out, err

可以使用以下命令运行任何shell命令。我在ubuntu上使用过它们。

import os
os.popen('your command here').read()

注意:自python 2.6起已弃用。现在必须使用subprocess.Popen。下面是示例

import subprocess

p = subprocess.Popen("Your command", shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()[0]
print p.split("\n")

这要简单得多,但只适用于Unix(包括Cygwin)和Python2.7。

import commands
print commands.getstatusoutput('wc -l file')

它返回一个元组(return_value, output)。

对于在Python2和Python3中都可以工作的解决方案,请使用subprocess模块:

from subprocess import Popen, PIPE
output = Popen(["date"],stdout=PIPE)
response = output.communicate()
print response

这里有一个解决方案,如果你想在进程运行或不运行时打印输出。


我还添加了当前工作目录,这对我来说很有用不止一次。


希望这个解决方案能帮助到别人:)。

import subprocess

def run_command(cmd_and_args, print_constantly=False, cwd=None):
"""Runs a system command.

:param cmd_and_args: the command to run with or without a Pipe (|).
:param print_constantly: If True then the output is logged in continuous until the command ended.
:param cwd: the current working directory (the directory from which you will like to execute the command)
:return: - a tuple containing the return code, the stdout and the stderr of the command
"""
output = []

process = subprocess.Popen(cmd_and_args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=cwd)

while True:
    next_line = process.stdout.readline()
    if next_line:
        output.append(str(next_line))
        if print_constantly:
            print(next_line)
    elif not process.poll():
        break

error = process.communicate()[1]

return process.returncode, '\n'.join(output), error