what does

lonecrow · 03-30-2006, 03:44 PM

does it mean to continue the command or?

Like this exemple,

Code:

bunzip2 filename | tar -xvf -

I understand the command, but still I can't figure out what | is doing there. Ive seen it often used with the grep command as well.

Sorry since it's probably a repost, but it's hard to make a search using only "|"

Thanks very much for your help!

acid_kewpie · 03-30-2006, 03:46 PM

the pipe means that the output of the first program is used as the input to the second.

sundialsvcs · 03-30-2006, 04:26 PM

This is what Unix-heads call a "pipe."

I would strongly invite you to surf (here and elsewhere) for a general introduction to the bash shell. I won't try to substitute for that here.

However, to answer the immediate question ...

Consider the following:

Code:

 ps -A | grep mysql

...

The shell will start both the ps command and the grep command.
The shell will "pipe" the output from the first command so that it becomes the input to the second.
The shell will wait for the two commands to end.

lonecrow · 03-30-2006, 04:49 PM

I am actually reading on that, hence the point of my question!
Thanks to both of you!