UNIX for Dummies Questions & Answers

hi everyone I'm newbie in this forum hope I can get some help here

I have a command in crontab that executed every 1 minute
sometime this command need more than 1 minute to finish
the problem is, the crontab execute this command although it's not finish processing yet and causing the system hang

is there any way that can set the crontab to not execute the command if it's not finish yet?

thanks before for your help

Hi,
One way I can think of is to put a check on the script that runs as a part of crontab. Whatever you want to do with the script you do after a check that if any command of similar name is still running. example: lets say if you are running /home/user/script.sh every one minute, then add a check

Code:

ps -ef | grep "script.sh" | grep -v grep

on your script.sh in the beginning

-Raja

check for the process before running your command in the script

write a pid file, or grep for the process

Code:

ps -ef |  grep processname | grep -v grep || yourcommand

or something like that

ok this my command in the crontab:
*/1 * * * * /usr/bin/php /var/www/xml_updater.php

now, where should I put the grep command that you guys mentioned above?

you write a script, from within the script you run your php command, and before that, you place the grep command

Code:

ps -ef |  grep  "[x]ml_updater.php"  || /usr/bin/php /var/www/xml_updater.php

hi Funk, thanks before for your help
I want to know what is exactly the code you give above do?

if returncode of grep is greater than zero, eq the process has not been found, execute your script (||)