Review Code: Tab-delimited parsing

#!/usr/bin/perl
# Takes a three-column, tab-delimited file and creates two hashes.
# The keys for both hashes will be the items in the first column,
# and the values will be the second and third column
###############################################################
use warnings;
use strict;
 
my $infile = shift @ARGV;
my %institute; # Hash for the 2nd column data
my %mutation;  # Hash for the 3rd column data
 
open(IN,'<', $infile) or die "Can't open file $infile: $!\n";
while(my $line = <IN>)
{
  chomp $line;
 
  # The following line checks for a header line,
  #   which in this case begins with "Sample"
  # Header lines can start with anything though,
  #   so it's really important to verify your input data first
  next if($line =~ /Sample/);
 
  # The split() function returns an array, so this next line
  #   puts each item in the returned array into three variables
  my ($sample, $inst, $mut) = split(/\t/,$line);
 
  # Then just assign the values to their respective hashes
  $institute{$sample} = $inst;
  $mutation{$sample} = $mut;
}
close(IN);
 
##Output
# Print columns in reversed order
print "Mut\tInst\tSample\n"; # print out a header
foreach my $key (sort keys %institute)
{
  my $ins = $institute{$key}; 
  my $mu = $mutation{$key};
  print "$mu\t$ins\t$key\n";
}