I see you are using if (defined $xxx{$yyy}) where you probably intended if (exists $xxx{$yyy})

In general it is useful to provide the fail reason for opens using $!:

open(NCLIST, $ncaccts) || die ("Cannot open $ncaccts: $!");

[download]

The line open($output, '>', 'output.txt' || die "Cannot open output file output.txt"); has a missing ) and (. It should be open($output, '>', 'output.txt') || die ("Cannot open output file output.txt: $!");

You should always use the three parameter open. It makes the input explicit and in other contexts where the file name is provided by the user avoids malicious effects from a user putting > at the start of a file name.

DWIM is Perl's answer to Gödel

In reply to Re^3: comparing lists by GrandFather
in thread comparing lists by Anonymous Monk

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