#!/usr/bin/perl;
use strict;
use warnings;
use 5.012;

my ($line, @newarr);

my @hashfile = <DATA>;
for my $line (@hashfile){
    $line =~ tr/\$//;
	if ( $line =~ /VAR1/ ) {
        $line =~ s/VAR1/my \%hash/;
        push @newarr, $line;
    } else {
        push @newarr, $line;
    }
}
for $_( @newarr) {
    say $_;
}

__DATA__
$VAR1 = {
          '' => '',
          '362520' => 'Fktn and Name: fukutin[Rattus norvegicus]',
          '375790' => 'AGRN and Name: agrin[Homo sapiens]',
          '3339' => 'HSPG2 and Name: heparan sulfate proteoglycan 2[Homo sapiens]',
          '1428' => 'CRYM and Name: crystallin, mu[Homo sapiens]',
	}