Shell script to start program if not running

3lixy · 08-07-2011, 01:38 PM

Hey guys,

I found this thread http://www.linuxquestions.org/questi...unning-625589/ but the code is a bit beyond me.

I am looking for assistance in creating a script that does the following (written in the style of PHP):

If (program A is running and program B is running) {
do nothing
}
elseif (program A is not running and program B is runnning) {
term program B
start program A
sleep 120
start program B
}
elseif (program A is running and program B is not running) {
start program B
}

I intend to run the script via crontab every hour.

The reason for the script is because program a tends to crash randomly (it terms itself) and program b is an interface to program A. When program A dies program B has to be restarted when program A is back running.

i am using Ubuntu 10.04 LTS.

Thanks for your help.

EricTRA · 08-07-2011, 01:51 PM

Hello and Welcome to LinuxQuestions,

You'll have a hard time finding someone here at LQ that will do all the work for you. You will learn a lot more if you try to write a shell script yourself and calling in our help if you cannot get it to work or are getting errors you cannot solve. To start you could read about Bash scripting at the following links:
Bash Guide for Beginners
Advanced Bash Scripting Guide

Basically, show us what you've got already and tell us where you have doubts or where it's failing and we'll help you out for sure.

Looking forward to your participation in the forums. Have fun with Linux.

Kind regards,

Eric

3lixy · 08-07-2011, 01:58 PM

Thanks Eric. A good starting place. I think I should be able to use my existing programming knowledge to make a good go at it

.

EricTRA · 08-07-2011, 02:01 PM

Quote:

Originally Posted by 3lixy

Thanks Eric. A good starting place. I think I should be able to use my existing programming knowledge to make a good go at it

.

Hello,

That's the spirit! Don't hesitate to post any questions or doubts here at LQ. Have fun with Linux.

Kind regards,

Eric

igadoter · 08-07-2011, 03:22 PM

This is "ola" script

Code:

#!/bin/bash

foo=""; bar=""
pgrep $1 > /dev/null ; foo=$?
pgrep $2 > /dev/null ; bar=$?

if [ $foo = "0" ] ; then
    if [ $bar = "1" ] ; then
          $2 &
           exit 0
    fi ;
else if [ $bar = "0" ] ; then
    pkill $2
    $1 &
    sleep
    $2 & 
   exit 0
    fi ;
fi ;

The command is

Code:

 
$ ola A B

Of course use on its own risk. Test first.