Hi my fasta file looks like:

>dddd

abcdef

>eeee

bcdef

There is no space between lines. I want to add 'aaaa' to the beginning of the sequences (i.e., abcdef and bcdef in the example). I used the following script but it gives me a connected long sequence. Can anyone help me identify the problem? Thanks XF 


use warnings;
use strict;
my $read_mid1 = 'Reads.fna';
my $read_mid1_correct = 'Reads_correct.fa';
open ( my $input_fh, "<", $read_mid1 );
open ( my $output_fh, ">", $read_mid1_correct);
while (my $line = <$input_fh> )
{
   unless ($line =~ /^>/)

  {
    $line =~ s/^/ACGAGTGCGT/;
  
    print $output_fh $line;
  }

}
close ( $input_fh );
close ( $output_fh );

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