#!/bin/perl
use strict;
use warnings;

local $/ = "\r\n";

my @frames = (1, 2, 3, -1, -2, -3 );  #six frames;
foreach my $frame (@frames) {
frame ($frame);

sub frame
{
my $f = shift;
open IN, $ARGV[0];

while (<IN>){
    chomp;      #each sequence should be in single line;
    my $m = length ($_);

    if(/^>(\w+)/){
     print ">$1"."_"."frame"."$f"."\n";
     }elsif($f > 0){
        my $frameseq = substr($_, $f-1, $m-$f+1);
        print "$frameseq\n";
    }elsif ($f <0){
        my $comprevseq = reverse $_;
        $comprevseq =~ tr/[A,T,C,G,a,t,c,g]/[T,A,G,C,t,a,g,c]/;  # sequence reverse complement;
        my $frameseq = substr ($comprevseq, abs($f)-1, $m-abs($f)+1);

        print "$frameseq\n";
    }
}
}
close IN;
}