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

改进以获得更好的日志记录。 为了获得更好的输出,可以使用迭代器。 从下面开始,我们变得更好

from subprocess import Popen, getstatusoutput, PIPE
def shell_command(cmd):
    result = Popen(cmd, shell=True, stdout=PIPE, stderr=PIPE)

    output = iter(result.stdout.readline, b'')
    error = iter(result.stderr.readline, b'')
    print("##### OutPut ###")
    for line in output:
        print(line.decode("utf-8"))
    print("###### Error ########")
    for line in error:
        print(error.decode("utf-8")) # Convert bytes to str

    status, terminal_output = run_command(cmd)
    print(terminal_output)

shell_command("ls") # this will display all the files & folders in directory

使用getstatusoutput的其他方法(容易理解)

from subprocess import Popen, getstatusoutput, PIPE

status_Code, output = getstausoutput(command)
print(output) # this will give the terminal output

# status_code, output = getstatusoutput("ls") # this will print the all files & folder available in the directory

其他回答

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

下面是一个简单而灵活的解决方案,适用于各种操作系统版本,以及Python 2和3,在shell模式下使用IPython:

from IPython.terminal.embed import InteractiveShellEmbed
my_shell = InteractiveShellEmbed()
result = my_shell.getoutput("echo hello world")
print(result)

Out: ['hello world']

它有几个优点

它只需要安装IPython,所以在使用它时,你真的不需要担心特定的Python或操作系统版本,它附带Jupyter -具有广泛的支持 它默认接受一个简单的字符串-所以不需要使用shell模式参数或字符串拆分,使它在我看来稍微干净一些 它还使替换变量甚至字符串本身的整个Python命令更加干净


为了演示:

var = "hello world "
result = my_shell.getoutput("echo {var*2}")
print(result)

Out: ['hello world hello world']

只是想给你一个额外的选择,特别是如果你已经安装了Jupyter

当然,如果你在一个实际的Jupyter笔记本,而不是一个.py脚本,你也可以总是这样做:

result = !echo hello world
print(result)

为了达到同样的目的。

可以将输出重定向到文本文件,然后将其读回来。

import subprocess
import os
import tempfile

def execute_to_file(command):
    """
    This function execute the command
    and pass its output to a tempfile then read it back
    It is usefull for process that deploy child process
    """
    temp_file = tempfile.NamedTemporaryFile(delete=False)
    temp_file.close()
    path = temp_file.name
    command = command + " > " + path
    proc = subprocess.run(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
    if proc.stderr:
        # if command failed return
        os.unlink(path)
        return
    with open(path, 'r') as f:
        data = f.read()
    os.unlink(path)
    return data

if __name__ == "__main__":
    path = "Somepath"
    command = 'ecls.exe /files ' + path
    print(execute(command))

这是一个棘手但超级简单的解决方案,适用于许多情况:

import os
os.system('sample_cmd > tmp')
print(open('tmp', 'r').read())

使用命令的输出创建一个临时文件(这里是tmp),您可以从中读取所需的输出。

备注: 如果是一次性作业,可以删除tmp文件。如果需要多次执行此操作,则不需要删除tmp。

os.remove('tmp')

根据@senderle的说法,如果你像我一样使用python3.6:

def sh(cmd, input=""):
    rst = subprocess.run(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, input=input.encode("utf-8"))
    assert rst.returncode == 0, rst.stderr.decode("utf-8")
    return rst.stdout.decode("utf-8")
sh("ls -a")

将完全像您在bash中运行命令一样