To get the ouput of a sytem call, you would want to do:
$ret_val = `yoursystemcall`;
How to get that to your local computer is up to you.
One, you can run and assign the output of your system call to the $ret_val variable all on your remote computer and then update a database with it's value (that DB can be on your local machine or remote machine depending on your DB access setup). Now, if you allow remote access to the DB, you can get the system call output from any allowed host.
Two, Although this is a nasty security issue, you could do:
# on your local machine
$ret_val = `ssh user@remote /path/to/executable/program`;
# if your remote program outputs anything, that
# value will now be in $ret_val for you use on the local
# computer
These are just suggestions on how to get that value back to your local machine. But the main thing is knowing how to get the output of a system call in general. Again,
$ret_val = `yoursystemcall`;
Update:
If you couldn't tell by my comment, "...Although this is a nasty security issue...", I suggest the DB method :o).