Python Parsing subprocess Output

Question

I am trying to save the output of

git remote show origin

with

  tempf = open('.tmp', 'w+')
  tempf2 = open('.tmp2', 'w+')
  subprocess.Popen(["git", "remote", "show", "origin"], stdout=tempf, stderr=tempf2)
  tempf.close()
  tempf2.close()
  output = open('.tmp', 'r')
  gitoutput = output.read()

and later parse the output with a regex.

However, the code above keeps returning None for gitoutput.

Is there something that I am missing? I am fairly confused as applying .seek(0) does not change the output and running cat .tmp shows the correct contents.

EDIT: stderr is also captured (stderr=tempf2) and thrown away as the git server produces unwanted output to the command line when running the script.

You can try subprocess.check_call instead

Andrew C
– Andrew C

2014-11-05 00:16:18 +00:00
Commented Nov 5, 2014 at 0:16 — Andrew C
– Andrew C, Commented Nov 5, 2014 at 0:16

Padraic Cunningham · Accepted Answer · 2014-11-05 00:25:54Z

1

Use .wait() with Popen

import subprocess
with open('.tmp', 'w+') as tempf,  open('.tmp2', 'w+') as tempf2:
    proc  = subprocess.Popen(["git", "remote", "show", "origin"], stdout=tempf, stderr=tempf2)
    proc.wait()
    tempf.seek(0)
    gitoutput = tempf.read()
print(gitoutput)

Or just use check_call:

with open('.tmp', 'w+') as tempf,  open('.tmp2', 'w+') as tempf2:
    proc  = subprocess.check_call(["git", "remote", "show", "origin"], stdout=tempf, stderr=tempf2)
    tempf.seek(0)
    gitoutput = tempf.read()
print(gitoutput)

answered Nov 5, 2014 at 0:25

Padraic Cunningham

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Comments

Hackaholic · Accepted Answer · 2014-11-04 23:59:42Z

0

try like this

import subprocess
child = subprocess.Popen(["git", "remote", "show", "origin"], stdout=subprocess.PIPE,shell=True)
msg,err = child.communicate()
print msg
print err

here communicate will return a tuple containing the output and error message that is (stdoutdata,stderrdata)

answered Nov 4, 2014 at 23:59

Hackaholic

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