system explains that 'The return value is the exit status of the program as returned by the "wait" call. To get the actual exit value divide by 256.'

This can be proved using the following commands (assuming you're on a *nix type of OS):

shell> perl -le 'print(system("true")>>8)'
0
shell> perl -le 'print(system("false")>>8)'
1

If you are only getting 0, that means either:

• Your commands are returning 0 even in the event of 'failure' - test your commands from the shell by running them and then typing echo $?
• You are running your commands in the background using &
• Something else

I'm sure if you provide more detailed information, we could answer your question better.