How to preserve data between executions of program

I am running a perl script on a HP-UX box. The script will execute every 15 minutes and will need to compare it's results with the results of the last time it executed.

I will need to store two variables (IsOccuring and ErrorCount) between the executions. What is the best way to do this?

Edit clarification:

It only compares the most recent execution to the current execution.

It doesn't matter if the value is lost between reboots.

And touching the fil开发者_C百科esystem is pretty much off limits.

If you can't touch the file system, try using a shared memory segment. There are helper modules for that like IPC::ShareLite, or you can use the shmget and related functions directly.

You'll have to store them in a file. This sort of file is often kept in /tmp, but any place where the user running the cron job has access would do. Make sure your script can handle the case where the file is missing.

You could create a separate process running a "remember stuff" service over your choice of IPC mechanism. This sounds like a rather tortured solution to "I don't want to touch the disk" but if it's important enough to offset a couple of days of development work (realistically, if you are new to IPC, and HP-SUX continues to live up to its name) then by all means read man perlipc for a start.

Does it have to be completely re-executed? Can you just have it running in a loop and sleeping for 15 minutes between iterations? Than you don't have to worry about saving the values externally, the program never stops.

I definitely think IPC is the way to go here.

I'd save off the data in a file. Then, inside the script I'd load the last results if the file exists.

Use module Storable to serialize Perl data structures, save them anywhere you want and deserialize them during next script execution.