Question

I’m trying to implement something similar to git log, which will only page the output if the log is of a certain length. If you’re not familiar with git, I’m essentially trying to achieve this:

python some_script.py | less

With some help from the paging implementation in python2.6/pydoc.py, I was able to come up with this:

import os
text = '...some text...'
pipe = os.popen('less', 'w')
pipe.write(text)
pipe.close()

which works great, but os.popen() is deprecated. I’ve considered writing to a temp file and calling less with its path, but that doesn’t seem ideal. Is this possible with subprocess? Any other ideas?

EDIT:

So I’ve gotten subprocess working. I was able to give it the text variable with Popen.communicate(text), but since I really want to redirect print statements, I’ve settled on this:

  import os, sys, subprocess, tempfile

  page = True
  if page:
      path = tempfile.mkstemp()[1]
      tmp_file = open(path, 'a')
      sys.stdout = tmp_file
  print '...some text...'
  if page:
      tmp_file.flush()
      tmp_file.close()
      p = subprocess.Popen(['less', path], stdin=subprocess.PIPE)
      p.communicate()
      sys.stdout = sys.__stdout__     

Of course, I’d end up wrapping it into functions. Does anyone see a problem with that?

Answer 1

Use subprocess.Popen instead.

http://docs.python.org/library/subprocess.html#subprocess-replacements

http://docs.python.org/library/subprocess.html#subprocess.Popen

There is even a note about this in the os.popen docs.

http://docs.python.org/library/os.html#os.popen