Hi, I know that you can use the head -1 command in unix to print the first line of a file. I have a data file and I need to read in the file, print the header of the input file to an output file, then do a number of other things aside from this. What command or function can I use to print the header line to an output file. You probably do not need to see my code but it is included for your reference. I don't want to change my code, rather just figure out a simple way to print the header of my input file to an output file. Thanks. 

 #!/usr/bin/perl

#use strict;
use warnings;



#print "Enter the input file name: ";
#my $filename = <STDIN>;
#chomp ($filename);

@ARGV == 1 or die "Invalid number of arguments. Please supply as argum
+ents: \n1) the input file listing all data to be used.";
my ($input_file) = @ARGV;

open (IN, "$input_file") or die "Cannot open file: $!";
#head -1 <IN>;
#my $firstline = IN;

my $x=0;
my @keys;
my @holder;
my @array_hash;
my $threshold=.03;
my $blank = "-";
my $nonsyn = "nonsynonymous";

open (OUTFILE, ">TEST_$input_file") or die "Cannot create an output fi
+le: $!";
while(my $line = <IN>)
{
    print OUTFILE head -1;
    chomp($line);
    $x++;
    if ($x==1)
    {
        (@keys)=split(/\t/, $line);
    }
    else
    {
        my $y=0;
        (@holder) = split(/\t/, $line);
        my %hash;
        for my $column (@holder)
        {
            $hash{$keys[$y]}=$column;
            $y++;
        }

#        -ne print OUTFILE; exit;
#        my $first = shift (@array_hash);
#        print OUTFILE $first;

        if ($hash{"1000_Genomes"} ne $blank)
        {
            if ($hash{"1000_Genomes"} <=  $threshold)
                    {
                        if ($hash{"Syn/Nonsyn"} eq $nonsyn)
                {        
                     print OUTFILE $line, "\n";
                }
                    }
        }
                if ($hash{"1000_Genomes"} eq $blank)
                {
                       # if ($hash{"1000_Genomes"} <=  $threshold)
                       # {
                                if ($hash{"Syn/Nonsyn"} eq $nonsyn)
                                {
                                        print OUTFILE $line, "\n";
                                }
                       # }
                }

    }

}

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In reply to Obtaining header from file (first line) - printing to output file by dkhalfe

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