SP   GC DC  ID  Descr   GI Locus LF
cat Ts All 5320 CGA1   1892 L2   3.1
dog Ts Sp  6420 beta 1 1849 L3   4.2
------------------------------------

The format of the data is the same in the four files.  



##</code><code>##

#!/usr/bin/perl -w
use strict;
use warnings;

my $infile1="file1.csv";
my $infile2="file2.csv";
my $infile3="file3.csv";
my $infile4="file4.csv";
open (my $in_fh1, "<", $infile1) or die "Can't open $infile1" ($!);
open (my $in_fh2, "<", $infile2) or die "Can't open $infile2" ($!);
open (my $in_fh3, "<", $infile3) or die "Can't open $infile3" ($!);
open (my $in_fh4, "<", $infile4) or die "Can't open $infile4" ($!);
open (my $out_fh, ">", "file1_4.csv");


while (defined(my $line1=<$in_fh1>) || defined (my $line2=<$in_fh2)|| defined (my $line3=<$in_fh3)|| defined (my $line4=<$in_fh4)
      ){
    chomp $line1;
    $line1=~s/\t/,/g;
    my @columnheadings=split (/\t/, $line1);
    my $headings=join(",", @columnheadings);
     chomp $line2;
    $line2=~s/\t/,/g;
    chomp $line3;
    $line3=~s/\t/,/g;
    chomp $line4;
    $line4=~s/\t/,/g;
    print $out_fh "$headings\n";
}