You might find a few hints if you use strict; and used -w or use warnings; (depending on your version of Perl).

In your foreach $guest loop your split is not acting on $guest as you have mis-placed your brackets. Because of this, you never find the matching record that you want to change, and so your file is never any different after execution. Warnings would have caught this problem.

--
I'd like to be able to assign to an luser

In reply to Re: problems editing a flat-file by Albannach
in thread problems editing a flat-file by Anonymous Monk

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