I think what you need, is best done from your originating server, by sending a command that will execute remotely, to check the last modification time of $remotefile

#!/usr/bin/perl -w

use strict;

my $remotefile = '/tmp/yourfile.conf';

my $remotestat = qx!
      ssh -2 -p 12345 172.16.16.82  'perl -e "print ((stat(qq~$remotef
+ile~))[9])" '
                   !;

print "\n$remotestat \n";
print "\n", scalar localtime($remotestat), "\n\n";
[download]

If your ssh setup is working properly, this should return the value you need from the remote server. You might then keep a comparison table locally so if you determine the file was edited by someone other than your script you could then act accordingly..

I would just like to add though, that planning the whole thing architecturally - diagram it! - before writing the app will ultimately save you time.. then the code writing will become the final task. It will also be easier to document, and explain to users, management, etc

It also seems to me that to make your app a little closer to bulletproof you should consider keeping versioned backups of the remote files -- having multiple users jumping in to edit a single file at will with no change control or revisioning is kinda crazy.