#!/usr/local/bin/perl -w
# use strict;
# use warnings;
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That should be:

#!/usr/local/bin/perl
use strict;
use warnings;
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if($#ARGV != 1)
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That is usually written as:

if(@ARGV != 2)
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chomp(@ARGV);
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There is no need to chomp the @ARGV array!

$dirname =~ s/\/$//g;
$output  =~ s/\/$//g;
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You are anchoring the pattern to the end of the string so the /g option is superfluous.

mkdir $output if (-d $output ==0);
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That would usually be written as:

mkdir $output or die "mkdir $output: $!" unless -d $output;
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