use Algorithm::Diff qw(diff sdiff LCS traverse_sequences);                      
my @seq1= split //,"1  AGCTGATCGAGCTAGTACCCTAGCTC 26";
my @seq2 =split //,"15 AGCTGATCGAGCTAGTACCCTATCTC 40";

my  @diffs = diff( \@seq1, \@seq2 );
foreach (@diffs) {
    foreach (@{$_}) {
       print join " " => @{$_},"\n";        
    }
    print "\n";
    
}

##</code><code>##

+ 1 5 

- 2   

- 25 G 
+ 25 T 

- 30 2 
+ 30 4 
- 31 6 
+ 31 0