Setting global variables from a crontab job
 

I've a simple test script:

#!/bin/bash

case $SET_THIS in
one) export SET_THIS=two
;;
two) export SET_THIS=three
;;
three) export SET_THIS=one
;;
*) export SET_THIS=one
;;
esac
echo $SET_THIS

It sets the $SET_THIS variable in the current shell if I run it will a '.' ie . ./setscript - but - how do I do this from running the command from a crontab job? Is it possibe? I would like the crontab job to know the previous value of the variable when the script starts...

Dave

Hi Davee

This depends on how the variable is set, from an interactive shell session or a previous running of the crontab script.
1 Set by an interactive shell
I think that the way to do this is to create a logout script that edits your bash/ksh rc file to reflect the current value of the variable or if the variable needs to be the same each time you log in then create a separate file that contains the value and then place '. var_file' at the start of the crontab script ie
.bash_logout contains
echo "export SET_THIS=$SET_THIS" > ~/.cron_set

.bashrc contains
. ~/.cron_set - to set SET_THIS on each shell invocation
or
crontab script contains
. ~/.cron_set - To only set SET_THIS when run from crontab

2 Set by previous crontab script
Simply add .
~/.cron_set - to the start of the crontab script
and
echo "export SET_THIS=$SET_THIS" > ~/.cron_set - to the end of the script.

Don't forget to give an initial value in ./.cron_set

Thanks for that! I'll give it a try and see what happens. It's one of these things that doesn't seem to be covered in any of my linux books.

Cheers, Dave