获得输出不断变化的子流程的输出

Question

我想捕获archlinux的pacman软件包管理器的输出。这样做时，我要处理它的输出，但也想将其显示给用户。

这里是我到目前为止所带的：-

import subprocess as sb
import sys

lol = sb.Popen('sudo pacman -Syy',stdout=sb.PIPE,shell=True)

while True:
    l = lol.stdout.readline().strip()

    if l and lol.poll() is not None:
        break

    sys.stdout.write(l.decode())
    sys.stdout.flush()

print("done")

但它打印此：-

❯ python test.py
:: Synchronizing package databases...downloading core.db...downloading extra.db...downloading community.db...downloading multilib.db...

卡住，也无法完成打印

这是我想要的

:: Synchronizing package databases...
 core                                                                     135.2 KiB   160 KiB/s 00:01 [############################################################] 100%
 extra                                                                   1706.7 KiB   470 KiB/s 00:04 [############################################################] 100%
 community                                                                  4.9 MiB  1107 KiB/s 00:05 [############################################################] 100%
 multilib                                                                 161.2 KiB  3.09 MiB/s 00:00 [############################################################] 100%

done

Answer 1

这是您要寻找的吗？

import subprocess as sb
import sys

lol = sb.Popen('sudo pacman -Syy',stdout=sb.PIPE,shell=True)

while True:
    l = lol.stdout.readline().strip()
    if lol.poll() is not None:
        break

    sys.stdout.write(l.decode())
    sys.stdout.flush()

print("done")

输出：

:: Synchronizing package databases...downloading core.db...downloading extra.db...downloading community.db...done

Answer 2

类似的方法可能对您有用：

import subprocess
import sys

# for py3 uncomment next line
# basestring = str


def cmd2args(cmd):
    """On linux we might need to split the command before executing...?
    """
    win32 = sys.platform == 'win32'
    if isinstance(cmd, basestring):
        if not win32 and cmd.startswith('cd '):
            return cmd
        else:
            return cmd if win32 else shlex.split(cmd)
    return cmd



def echorun(cmd, curdir='.'):
    """Send stderr to terminal, but yield stdout one line at a time.
    """
    popen = subprocess.Popen(cmd2args(cmd),
                             stdout=subprocess.PIPE,
                             stderr=subprocess.STDOUT,
                             cwd=curdir,
                             shell=sys.platform == 'win32',
                             universal_newlines=True)
    if popen.stdout is not None:
        for line in iter(popen.stdout.readline, ""):
            if sys.version_info.major == 3 and isinstance(line, str):
                yield  line
            else:
                yield line.decode()

    exitcode = popen.wait()
    if exitcode != 0:
        raise RuntimeError("Exitcode: %d" % exitcode)

用途将是：

    for line in echorun('sudo pacman -Syy', curdir):
        print(line)