Python 子进程 popen 管道

Question

我正在尝试在 python 中发出命令并读取输入并将其解析回来。这是我尝试发出的命令(在命令行上运行时的示例)

-bash-3.2$ echo "passthru TST,1234" | ./vsh -a 127.0.0.1 -p 7000
PASSTHRU TST,1234
udp_send_command: timed out waiting for response
-bash-3.2$

我正在尝试使用 python 子进程

            vsh_command = ' "passthru ' + cmd + '" | ./vsh -a ' + ip_address + ' -p ' + port
            print vsh_command
            new_command = ['echo', vsh_command]
            print new_command
            proc = subprocess.Popen(new_command,
                    stdout=subprocess.PIPE,
                    stderr=subprocess.PIPE,
                    stdin=subprocess.PIPE,
                    shell=True)
            print '1'
            out_2, err = proc.communicate()
            print out_2
            print '2'
            rcv = out_2.splitlines()
            print '3'
            for r in rcv:
                    print '     ' + r
            print '4'

`

 "passthru TST,1234" | ./vsh -a 127.0.0.1 -p 7000
['echo', ' "passthru TST,1234" | ./vsh -a 127.0.0.1 -p 7000']
1


2
3

4

是一个|子进程无法使用命令？如果是这样，还有另一种方法可以运行此 shell 命令并获取输入吗？

更新:(使用 shell=true 命令的单个字符串)

`vsh_command = 'echo "passthru ' + cmd + '" | ./vsh -a ' + ip_address + ' -p ' + port
            print vsh_command
            proc = subprocess.Popen(vsh_command,
                    stdout=subprocess.PIPE,
                    stderr=subprocess.PIPE,
                    stdin=subprocess.PIPE,
                    shell=True)
            print '1'
            out_2, err = proc.communicate()
            print out_2
            print '2'
            rcv = out_2.splitlines()
            print '3'
            for r in rcv:
                    print '     ' + r
            print '4'

`

运行(python 脚本)

echo "passthru TST,1234" | ./vsh -a 127.0.0.1 -p 7000
1
PASSTHRU TST,1234

2
3
     PASSTHRU TST,1234
4
SUCCESS

仍然不完全是我想要的，看起来它只是执行 echo 命令而不是管道

编辑#2

            p = Popen(["./vsh", "-a", ip_address, "-p", str(port)],stdin=PIPE, stdout=PIPE)
            out, err =  p.communicate("passthru TST,1234")
            print '----------'
            print out

输出:

-bash-3.2$ python mfd_ascii_test.py
udp_send_command: timed out waiting for response
----------
PASSTHRU TST,1234

-bash-3.2$

out是echo的结果，而不是'udp_send_command: timed out waiting for response'

Answer 1

如果要将输出从一个进程通过管道传送到另一个进程，可以将标准输出从一个进程传送到另一个进程的标准输入:

from subprocess import PIPE,Popen

p1 = Popen(["echo", "passthru TST,1234"],stdout=PIPE)

p2 = Popen(["./vsh", "-a", "127.0.0.1", "-p", "7000"],stdin=p1.stdout,stdout=PIPE,stderr=PIPE)
p1.stdout.close()
out, err = p2.communicate()

如果您想使用管道字符，则需要设置 shell=True 并传递单个字符串:

from subprocess import check_output

out = check_output('echo "passthru TST,1234" | ./vsh -a 127.0.0.1 -p 7000',shell=True)