fasta: delete sequences after n length

Question

I have multiple fasta files with 1000s of seqs in each file of varying length. I would like to keep only the first 200 (n) bases from each sequence. How can I do this in Perl?

Answer 1

Difficult to understand exactly what you mean without seeing an example but if you only need the first 200 characters per line just use cut:

cut -c1-200 file