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'
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。
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