我知道如何使用cmd = subprocess.Popen然后使用subprocess.communicate来运行命令。大多数时候,我使用一个用shlex.split标记的字符串作为Popen的'argv‘参数。以"ls -l“为例:
import subprocess
import shlex
print subprocess.Popen(shlex.split(r'ls -l'), stdin = subprocess.PIPE, stdout = subprocess.PIPE, stderr = subprocess.PIPE).communicate()[0]
然而,管道似乎不起作用。例如,下面的示例返回注释:
import subprocess
import shlex
print subprocess.Popen(shlex.split(r'ls -l | sed "s/a/b/g"'), stdin = subprocess.PIPE, stdout = subprocess.PIPE, stderr = subprocess.PIPE).communicate()[0]
你能告诉我我哪里做错了吗?
Thx
发布于 2011-09-12 22:58:22
我认为你想在这里实例化两个单独的Popen对象,一个用于'ls‘,另一个用于'sed’。您需要将第一个Popen对象的stdout
属性作为stdin
参数传递给第二个Popen对象。
示例:
p1 = subprocess.Popen('ls ...', stdout=subprocess.PIPE)
p2 = subprocess.Popen('sed ...', stdin=p1.stdout, stdout=subprocess.PIPE)
print p2.communicate()
如果你有更多的命令,你可以继续这样链接:
p3 = subprocess.Popen('prog', stdin=p2.stdout, ...)
有关如何使用子进程的更多信息,请参阅subprocess documentation。
发布于 2015-04-21 02:18:30
我做了一个小函数来帮助处理管道,希望它能帮上忙。它将在需要时链接Popen。
from subprocess import Popen, PIPE
import shlex
def run(cmd):
"""Runs the given command locally and returns the output, err and exit_code."""
if "|" in cmd:
cmd_parts = cmd.split('|')
else:
cmd_parts = []
cmd_parts.append(cmd)
i = 0
p = {}
for cmd_part in cmd_parts:
cmd_part = cmd_part.strip()
if i == 0:
p[i]=Popen(shlex.split(cmd_part),stdin=None, stdout=PIPE, stderr=PIPE)
else:
p[i]=Popen(shlex.split(cmd_part),stdin=p[i-1].stdout, stdout=PIPE, stderr=PIPE)
i = i +1
(output, err) = p[i-1].communicate()
exit_code = p[0].wait()
return str(output), str(err), exit_code
output, err, exit_code = run("ls -lha /var/log | grep syslog | grep gz")
if exit_code != 0:
print "Output:"
print output
print "Error:"
print err
# Handle error here
else:
# Be happy :D
print output
发布于 2017-03-22 07:38:32
"""
Why don't you use shell
"""
def output_shell(line):
try:
shell_command = Popen(line, stdout=PIPE, stderr=PIPE, shell=True)
except OSError:
return None
except ValueError:
return None
(output, err) = shell_command.communicate()
shell_command.wait()
if shell_command.returncode != 0:
print "Shell command failed to execute"
return None
return str(output)
https://stackoverflow.com/questions/7389662
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