http://www.perlmonks.org?node_id=1008740


in reply to opened file being overwritten

This is a good time to start always using the three parameter version of open and lexical file handles:

open my $file4In, '<', $fileName or die "Could not open $filename: $!\ +n";

Appending In or Out to your file handles helps as a sanity and consistency check.

You get even more linty goodness if you always use strictures (use strict; use warnings;).

Note too that showing why an open failed often is at least as useful as showing which open failed.

True laziness is hard work