Hi liorlew, welcome to the Monastery!

Under strict, or more precisely, strict 'vars' , you have to declare each variable before you use it. You haven't declared $undefvar . 

use strict;
use warnings;
my $newvar = 0;
my $undefvar;            # Declared, but undefined.
if (defined $undefvar) {
    $newvar = $undefvar;
}

[download]

Update: refs → vars 

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

[download]

In reply to Re: if defined not working by choroba
in thread if defined not working by liorlew

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