use Data::Dumper; 
use List::Util qw/sum/; 
sub avg { sum(@_) / @_ } 
 
open (IN, "$ARGV[0]") || die "nope\n"; 
my %hash; 
 
# Read data line by line 
while (<IN>) 
{ 
    chomp; 
    my $line = $_; 
 
    my $key = (split/\t/, $line)[0]; 
    push @{ $hash{$key} }, $line; 
} 
my $avg	= avg @{ $hash{$key} }; 
print $avg,"\n"; 
close IN;