undef $/; my $sequence = ; $sequence =~ s/\s+//g; my $length = 60; for ( my $pos = 0 ; $pos < length($sequence) ; $pos += $length ) { print substr($sequence, $pos, $length), "\n"; } __DATA__ GAGGGTGCAATCTACAAGAGTGCGGGTTCGCGTTCAGTCCAAGCTGAACATAAACGCAAC GCAAGGCCCCTCGACGCAGATACCGCGCTCAGGAGCATTCGAGAAGCCGAAGAAAATTCG AAGACGAGGACCAGCTACACTGCGGACGGACTTCGGGCATGGAGGGCCAGTTCCAG GTTGGCAAGGAGGAGGTCATCCAAGCATGGTACATGGACGACAGTGAAGAGGACCAGAGG CTTCCTCATCATCGTGAGCCCAAAGAATTCATTCCTCTCGACAAACTTTCCG AACTAGGAATATTAAGCTGGCGCCTAAATGCTGATGATTGGGAGAATGATGAGAACCTCA AGAAAATTCGTGAAGCCAGGGGTTACTCTTACATG GACATTTGTGATGTGTGCCCAGAGAAGTTGCCAAATTACGAGGCTAAGATAAAGAATTTC TTTGAAGAACACTTGCATACTGATGAAGAGATACGATATTGCCTTGAGGGTAGCG GCTACTTTGATGTGAGGGACCAAGATGATCAGTGGATCCGTGTAGCGGTAAAGAAAGGGG GCATGATCGTTTTGCCTGCAGGAATGTATCATCGCTTTACGTTGGATAGTGACAACTACA TCAAG GCAATGCGTCTATTTGTGGGTGAGCCTGTCTGGACACCATACAATCGTCCGCATGACCAT CTCCCGGCTAG