#!/usr/bin/env perl use strict; use warnings; my %data; while (<>) { my ( $key, $value ) = split; push( @{ $data{$key} }, $value ); } foreach my $key ( sort keys %data ) { if ( @{ $data{$key} } >= @ARGV ) { print join( "\t", $key, @{ $data{$key} } ), "\n"; } }