如何将此tar命令作为参数传递给python子进程

Question

If I am running the command that is specified in the args on the terminal then it goes successfully on terminal but doing the same in python program is not working; I am seeing junk characters in the screen to the size of the input tar file and lot of xterm words too;

I feel the problem is handling the ' ' letters in the args;

 import subprocess

 try:
     args = "cat parsing.tgz <(echo -n ''| gzip)> new-file.tgz".split()
     subprocess.check_call(args)
 except subprocess.CalledProcessError as e:
     print e

Answer 1

I am not specialist, but this i found - this commands not working in sh , but working in bash :

$ sh -c "cat parsing.tgz <(echo -n ''| gzip)> new-file.tgz"
sh: -c: line 0: syntax error near unexpected token `('
sh: -c: line 0: `cat parsing.tgz <(echo -n ''| gzip)> new-file.tgz'
$
$ bash -c "cat parsing.tgz <(echo -n ''| gzip)> new-file.tgz"
$

Thats a reason why it not work in subprocess directly. This code looks work fine:

import subprocess
command = "cat parsing.tgz <(echo -n ''| gzip)> new-file.tgz"
subprocess.Popen(command, shell=True, executable='/bin/bash')

Answer 2

I tried a number of alternatives, and none of them were satisfactory. The best I found was switching over to Popen .

# this should have the a similar signature to check_call 
def run_in_shell(*args):
    # unfortunately, `args` won't be escaped as it is actually a string argument to bash.
    proc = subprocess.Popen(['/bin/bash', '-c', ' '.join(args)])
    # This will also work, though I have found users who had problems with it.
    # proc = subprocess.Popen(' '.join(args), shell=True, executable='/bin/bash')
    stat = proc.wait()
    if stat != 0:
        subprocess.CalledProcessError(returncode=stat, cmd=command)
    return stat

run_in_shell("cat parsing.tgz <(echo -n ''| gzip)> new-file.tgz")

As a note: /bin/sh has problems with the unescaped parentheses. If you don't want to specify '/bin/bash' above, then you will need to escape the paren:

args = 'cat parsing.tgz <\\(echo -n ''| gzip\\)> new-file.tgz'