Shell Programming and Scripting

Hey All,

Quick question...

I'm writing a short script to check if a continuous port is running on a server.

I'm using "ps -ef | grep -v grep | grep processName" and I was wondering if it was better/more reliable to just check the
return code from the command or if its better to pipe to 'wc -l' and check if it is '1' or not?

I was just curious if one method was more reliable then the other?

The server is "AIX 6"...

Thanks in Advance,
Matt

They both do the exact same thing, but the return code method is simpler and costs one less process. The simpler way tends to be the best.

However: You're putting yourself through a lot of needless pain here:

Code:

if pgrep processName >/dev/null
then
...
else
...
fi

You should find pgrep in most places.

Hey Corona, thanks for the reply!

Ok cool... I've never used "pgrep" before, thanks I'll give that a try.

Thanks Again,
Matt

also, pgrep directly prints pid's, so if you need them as output it can be used unfiltered.

Ugghhh, nevermind....

Looks like the UNIX server (which is probably older then myself, or pretty darn close) doesn't have the pgrep command.

It only has: grep, egrep, fgrep and zgrep...

Code:

ls -l /usr/bin | grep "grep"
-r-xr-xr-x    3 bin      bin           34052 Jan  7 2011  egrep
-r-xr-xr-x    3 bin      bin           34052 Jan  7 2011  fgrep
-r-xr-xr-x    3 bin      bin           34052 Jan  7 2011  grep
lrwxrwxrwx    1 root     system           27 May 12 2012  zgrep -> /usr/opt/freeware/bin/zgrep

Oh well, thanks anyways... I'll probably be able to get some use out of that on a slightly newer server. I guess I'll just go with the original idea.



Thanks Again,
Matt

What is it? uname -a It'd be useful to know where pgrep is absent... I thought it was somewhat universal.

Yea I thought the same thing...

It's a pretty ancient system that I "think" we plan on replacing soon... FINGERS CROSSED!
Running mostly dreaded UniData stuff.

Code:

#uname -a
AIX hostName 1 6 00C595524C00

No worries though I should be fine with the 'ps | grep' commands...


Thanks Again,
Matt