Python 无需打印到控制台即可获取系统 ping 的输出

Get output of system ping without printing to the console

提问by pelos

I want to call pingfrom Python and get the output. I tried the following:

我想ping从 Python调用并获取输出。我尝试了以下方法：

response = os.system("ping "+ "- c")

However, this prints to the console, which I don't want.

但是，这会打印到控制台，这是我不想要的。

PING 10.10.0.100 (10.10.0.100) 56(86) bytes of data.
64 bytes from 10.10.0.100: icmp_seq=1 ttl=63 time=0.713 ms
64 bytes from 10.10.0.100: icmp_seq=2 ttl=63 time=1.15 ms

Is there a way to not print to the console and just get the result?

有没有办法不打印到控制台而只得到结果？

采纳答案by davidism

To get the output of a command, use subprocess.check_output. It raises an error if the command fails, so surround it in a tryblock.

要获取命令的输出，请使用subprocess.check_output. 如果命令失败，它会引发错误，因此将其括在一个try块中。

import subprocess

try:
    response = subprocess.check_output(
        ['ping', '-c', '3', '10.10.0.100'],
        stderr=subprocess.STDOUT,  # get all output
        universal_newlines=True  # return string not bytes
    )
except subprocess.CalledProcessError:
    response = None

---

---

To use pingto know whether an address is responding, use its return value, which is 0 for success. subprocess.check_callwill raise and error if the return value is not 0. To suppress output, redirect stdoutand stderr. With Python 3 you can use subprocess.DEVNULLrather than opening the null file in a block.

要ping知道地址是否正在响应，请使用其返回值，成功为 0。 subprocess.check_call如果返回值不为 0，则会引发并出错。要抑制输出，请重定向stdout和stderr。使用 Python 3，您可以使用subprocess.DEVNULL而不是在块中打开空文件。

import os
import subprocess

with open(os.devnull, 'w') as DEVNULL:
    try:
        subprocess.check_call(
            ['ping', '-c', '3', '10.10.0.100'],
            stdout=DEVNULL,  # suppress output
            stderr=DEVNULL
        )
        is_up = True
    except subprocess.CalledProcessError:
        is_up = False

---

---

_{In general, use subprocesscalls, which, as the docs describe, are intended to replace os.system.}

_{一般来说，使用subprocess调用，正如文档描述的那样，旨在替换os.system.}

回答by Martijn Pieters

If you only need to check if the ping was successful, look at the status code; pingreturns 2for a failed ping, 0for a success.

如果只需要检查ping是否成功，看状态码；ping返回2失败的 ping，0成功。

I'd use subprocess.Popen()(and notsubprocess.check_call()as that raises an exception when pingreports the host is down, complicating handling). Redirect stdoutto a pipe so you can read it from Python:

我会使用subprocess.Popen()（而不是subprocess.check_call()在ping报告主机关闭时引发异常，从而使处理复杂化）。重定向stdout到管道，以便您可以从 Python 中读取它：

ipaddress = '198.252.206.140'  # guess who
proc = subprocess.Popen(
    ['ping', '-c', '3', ipaddress],
    stdout=subprocess.PIPE)
stdout, stderr = proc.communicate()
if proc.returncode == 0:
    print('{} is UP'.format(ipaddress))
    print('ping output:')
    print(stdout.decode('ASCII'))

You can switch to subprocess.DEVNULL^*if you want to ignore the output; use proc.wait()to wait for pingto exit; you can add -qto have pingdo less work, as it'll produce less output with that switch:

如果你想忽略输出，你可以切换到^*；用于等待退出；您可以添加以减少工作量，因为使用该开关会产生更少的输出：subprocess.DEVNULLproc.wait()ping-qping

proc = subprocess.Popen(
    ['ping', '-q', '-c', '3', ipaddress],
    stdout=subprocess.DEVNULL)
proc.wait()
if proc.returncode == 0:
    print('{} is UP'.format(ipaddress))

In both cases, proc.returncodecan tell you more about why the ping failed, depending on your pingimplementation. See man pingfor details. On OS X the manpage states:

在这两种情况下，proc.returncode都可以告诉您更多有关 ping 失败的原因，具体取决于您的ping实施。详情请参阅man ping。在 OS X 上，联机帮助页指出：

EXIT STATUS
     The ping utility exits with one of the following values:

     0       At least one response was heard from the specified host.

     2       The transmission was successful but no responses were received.

     any other value
             An error occurred.  These values are defined in <sysexits.h>.

and man sysexitslists further error codes.

并man sysexits列出更多错误代码。

The latter form (ignoring the output) can be simplified by using subprocess.call(), which combines the proc.wait()with a proc.returncodereturn:

后一种形式（忽略输出）可以通过使用 来简化subprocess.call()，它将proc.wait()与proc.returncode返回结合起来：

status = subprocess.call(
    ['ping', '-q', '-c', '3', ipaddress],
    stdout=subprocess.DEVNULL)
if status == 0:
    print('{} is UP'.format(ipaddress))

---

---

^*subprocess.DEVNULLis new in Python 3.3; use open(os.devnull, 'wb')in it's place in older Python versions, making use of the os.devnullvalue, e.g.:

^*subprocess.DEVNULL是 Python 3.3 中的新功能；open(os.devnull, 'wb')在较旧的 Python 版本中使用它，利用os.devnullvalue，例如：

status = subprocess.call(
    ['ping', '-q', '-c', '3', ipaddress],
    stdout=open(os.devnull, 'wb'))