我如何在Python中命名一个外部命令,就好像我把它写在一个<unk>或命令中?


当前回答

您可以使用 Popen 从子过程模块运行任何命令。

from subprocess import Popen

首先,一个命令对象是创建的,所有你想要运行的论点。 例如,在下面的剪辑中,指令对象是由所有论点组成的:

cmd = (
        "gunicorn "
        "-c gunicorn_conf.py "
        "-w {workers} "
        "--timeout {timeout} "
        "-b {address}:{port} "
        "--limit-request-line 0 "
        "--limit-request-field_size 0 "
        "--log-level debug "
        "--max-requests {max_requests} "
        "manage:app").format(**locals())

然后这个命令对象与Popen一起使用,以启动一个过程:

process = Popen(cmd, shell=True)

这个过程也可以根据任何信号结束,使用下面的代码线:

Popen.terminate(process)

你可以等到完成上述命令的执行:

process.wait()

其他回答

下面是我的两个百分点:在我看来,这是处理外部命令时最好的做法......

这些是执行方法的回报值......

pass, stdout, stderr = execute(["ls","-la"],"/home/user/desktop")

这是执行方法......

def execute(cmdArray,workingDir):

    stdout = ''
    stderr = ''

    try:
        try:
            process = subprocess.Popen(cmdArray,cwd=workingDir, stdout=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=1)
        except OSError:
            return [False, '', 'ERROR : command(' + ' '.join(cmdArray) + ') could not get executed!']

        for line in iter(process.stdout.readline, b''):

            try:
                echoLine = line.decode("utf-8")
            except:
                echoLine = str(line)

            stdout += echoLine

        for line in iter(process.stderr.readline, b''):

            try:
                echoLine = line.decode("utf-8")
            except:
                echoLine = str(line)

            stderr += echoLine

    except (KeyboardInterrupt,SystemExit) as err:
        return [False,'',str(err)]

    process.stdout.close()

    returnCode = process.wait()
    if returnCode != 0 or stderr != '':
        return [False, stdout, stderr]
    else:
        return [True, stdout, stderr]

2015 年更新: Python 3.5 添加了 subprocess.run 比 subprocess.Popen 更容易使用。

>>> subprocess.run(["ls", "-l"])  # doesn't capture output
CompletedProcess(args=['ls', '-l'], returncode=0)

>>> subprocess.run("exit 1", shell=True, check=True)
Traceback (most recent call last):
  ...
subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

>>> subprocess.run(["ls", "-l", "/dev/null"], capture_output=True)
CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,
stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n', stderr=b'')

我用的是Python 3.6+:

import subprocess
def execute(cmd):
    """
        Purpose  : To execute a command and return exit status
        Argument : cmd - command to execute
        Return   : result, exit_code
    """
    process = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    (result, error) = process.communicate()
    rc = process.wait()
    if rc != 0:
        print ("Error: failed to execute command: ", cmd)
        print (error.rstrip().decode("utf-8"))
    return result.rstrip().decode("utf-8"), serror.rstrip().decode("utf-8")
# def

使用Python模块的Popen函数是运行Linux命令的最简单方式,Popen.communicate()函数将为您的命令提供输出。

import subprocess

..
process = subprocess.Popen(..)   # Pass command and arguments to the function
stdout, stderr = process.communicate()   # Get command output and error
..

我倾向于与shlex一起使用子过程(以处理引用的绳子的逃避):

>>> import subprocess, shlex
>>> command = 'ls -l "/your/path/with spaces/"'
>>> call_params = shlex.split(command)
>>> print call_params
["ls", "-l", "/your/path/with spaces/"]
>>> subprocess.call(call_params)