process grepping returns itself Post: 90885

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Top Forums Shell Programming and Scripting process grepping returns itself Post 90885 by smtpgeek on Monday 28th of November 2005 02:55:04 PM

11-28-2005

Registered User

process grepping returns itself

I am trying to write a script to make a ssh tunnel persist. I am writing it to check the existence of the tunnel on port 3307 and if it is not found start it:

#!/usr/local/bin/bash
# ~/my_tunnel.sh
tunnel_up=`ps ax|grep 3307`
if [ "${tunnel_up}" = "" ]; then
ssh -fNg -C -L 3307:127.0.0.1:3306 bob@db.webstakez.com & 2>/dev/null
fi

I believe that this is not working because the grep is returning a value for the actual grep command even when the tunnel is down. As an example, I check for anything on port 3308 since the tunnel is up:

$ ps waux|grep 3308
10014 18755 0.0 0.0 1428 440 pts/0 S 12:53 0:00 grep 3308

This is a Linux system, 2.4.20-021stab028.3.777-enterprise #1 and grep does not act this way on my freebsd box. What can I do to so that this will not return the actual grep?

TIA,
Bob

smtpgeek

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LEARN ABOUT BSD

zgrep

ZGREP(1)						      General Commands Manual							  ZGREP(1)

NAME

       zgrep - search possibly compressed files for a regular expression

SYNOPSIS

       zgrep [ grep_options ] [ -e ] pattern filename...

DESCRIPTION

       Zgrep  invokes  grep  on  compressed  or  gzipped  files.   These  grep	options  will  cause  zgrep  to  terminate  with  an  error  code:
       (-[drRzZ]|--di*|--exc*|--inc*|--rec*|--nu*).  All other options specified are passed directly to grep.  If no file is specified,  then  the
       standard input is decompressed if necessary and fed to grep.  Otherwise the given files are uncompressed if necessary and fed to grep.

       If the GREP environment variable is set, zgrep uses it as the grep program to be invoked.

EXIT CODE

       2 - An option that is not supported was specified.

AUTHOR

       Charles Levert (charles@comm.polymtl.ca)

SEE ALSO

       grep(1), gzexe(1), gzip(1), zdiff(1), zforce(1), zmore(1), znew(1)

																	  ZGREP(1)