By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
449,215 Members | 1,920 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 449,215 IT Pros & Developers. It's quick & easy.

subprocess.Popen and replacing the shell pipe line

P: n/a
I need to chain together three linux commands and get the final output. I read
the documentation for Popen in the subprocess module for replacing the shell
pipe line. I followed the example and keep getting a 0 where I should be
getting a 1.

I am trying to do this:
grep "Sep 22" /var/log/auth.log | grep "Illegal user" | wc -l
which returns a 1 when I run this manually.

This is what I did with python:

p1 = Popen(['grep', '"Sep 22"', '/var/log/auth.log'], stdout=PIPE)
p2 = Popen(['grep', '"Illegal user"'], stdin=p1.stdout, stdout=PIPE)
p3 = Popen(['wc', '-l'], stdin=p2.stdout, stdout=PIPE)
print p3.stdout.read()

which always prints a 0. What am I doing wrong?

Thanks,
Tom
Sep 22 '05 #1
Share this question for a faster answer!
Share on Google+

This discussion thread is closed

Replies have been disabled for this discussion.