perl -nle 'chomp;tr/a-z/A-Z/;next if /[^ATCG]/;$l=length();$c=0;for $m(5..$l){print substr($_,$c++,5)}' uniBNL_SSR_fasta.txt.input_library.txt | perl -nle '$c{$_}++ for split/\W/;}print map {"$_:$c{$_}\n"} sort{$c{$b}<=>$c{$a}}keys %c;{' -