没想到居然没人提到超时

Timeout 5 ping -c 3 somehost

显然，这并不适用于每个用例，但如果您处理的是一个简单的脚本，那么这是很难克服的。

mac用户也可以通过homebrew在coreutils中使用gtimeout。

有时需要处理(ffmpeg)而不使用communication()，在这种情况下需要异步超时，这是使用ttldict实现的一种实用方法

PIP安装ttldict

from ttldict import  TTLOrderedDict   
sp_timeout = TTLOrderedDict(default_ttl=10)

def kill_on_timeout(done, proc):
    while True:
        now = time.time()
        if sp_timeout.get('exp_time') == None:
                proc.kill()
                break
    
process = subprocess.Popen(cmd, stdout=subprocess.PIPE, text=True, stderr=subprocess.STDOUT)
            
sp_timeout['exp_time'] = time.time()
            
done = Event()
watcher = Thread(target=kill_on_timeout, args=(done, process))
watcher.daemon = True
watcher.start()
done.set()

for line in process.stdout:
.......

在Python 3.3+中:

from subprocess import STDOUT, check_output

output = check_output(cmd, stderr=STDOUT, timeout=seconds)

输出是一个字节字符串，包含命令合并的标准输出、标准输出数据。

与proc. communication()方法不同，check_output在问题文本中指定的非零退出状态上引发CalledProcessError。

我删除了shell=True，因为它经常被不必要地使用。如果cmd确实需要它，您总是可以将它添加回来。如果你添加shell=True，也就是说，如果子进程产生了自己的后代;check_output()的返回时间可能比超时时间晚得多，请参见子进程超时失败。

超时特性在Python 2中可用。X通过3.2+ subprocess模块的subprocess32后端端口实现。

python 2.7

import time
import subprocess

def run_command(cmd, timeout=0):
    start_time = time.time()
    df = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    while timeout and df.poll() == None:
        if time.time()-start_time >= timeout:
            df.kill()
            return -1, ""
    output = '\n'.join(df.communicate()).strip()
    return df.returncode, output

这是我的解决方案，我使用线程和事件:

import subprocess
from threading import Thread, Event

def kill_on_timeout(done, timeout, proc):
    if not done.wait(timeout):
        proc.kill()

def exec_command(command, timeout):

    done = Event()
    proc = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    watcher = Thread(target=kill_on_timeout, args=(done, timeout, proc))
    watcher.daemon = True
    watcher.start()

    data, stderr = proc.communicate()
    done.set()

    return data, stderr, proc.returncode

在行动:

In [2]: exec_command(['sleep', '10'], 5)
Out[2]: ('', '', -9)

In [3]: exec_command(['sleep', '10'], 11)
Out[3]: ('', '', 0)

下面是Alex Martelli的解决方案，它是一个具有适当进程终止的模块。其他方法不起作用，因为它们没有使用proc. communication()。所以如果你有一个产生大量输出的进程，它会填满它的输出缓冲区，然后阻塞，直到你从中读取一些东西。

from os import kill
from signal import alarm, signal, SIGALRM, SIGKILL
from subprocess import PIPE, Popen

def run(args, cwd = None, shell = False, kill_tree = True, timeout = -1, env = None):
    '''
    Run a command with a timeout after which it will be forcibly
    killed.
    '''
    class Alarm(Exception):
        pass
    def alarm_handler(signum, frame):
        raise Alarm
    p = Popen(args, shell = shell, cwd = cwd, stdout = PIPE, stderr = PIPE, env = env)
    if timeout != -1:
        signal(SIGALRM, alarm_handler)
        alarm(timeout)
    try:
        stdout, stderr = p.communicate()
        if timeout != -1:
            alarm(0)
    except Alarm:
        pids = [p.pid]
        if kill_tree:
            pids.extend(get_process_children(p.pid))
        for pid in pids:
            # process might have died before getting to this line
            # so wrap to avoid OSError: no such process
            try: 
                kill(pid, SIGKILL)
            except OSError:
                pass
        return -9, '', ''
    return p.returncode, stdout, stderr

def get_process_children(pid):
    p = Popen('ps --no-headers -o pid --ppid %d' % pid, shell = True,
              stdout = PIPE, stderr = PIPE)
    stdout, stderr = p.communicate()
    return [int(p) for p in stdout.split()]

if __name__ == '__main__':
    print run('find /', shell = True, timeout = 3)
    print run('find', shell = True)