new_contents: #! /usr/bin/env python3
  
  import os, argparse
  
  def split_fs(output_dir_fn):
  	i = 0
  	while True:
  		i += 1
  		fn = output_dir_fn + '/' + str(i) + '.fna'
  		yield open(fn, 'w'), i
  
  parser = argparse.ArgumentParser(
  	description='Split a file containing all the sequences in multiple files')
  parser.add_argument('input_file', help='Fasta file containing all the sequences')
  parser.add_argument('output_dir', help='Output directory')
  args = parser.parse_args()
  
  input_f = args.input_file
  output_dir_fn = args.output_dir
  
  start_seq = '>'
  split_f = split_fs(output_dir_fn)
  outfile = None
  
  with open(input_f, 'r') as fasta:
  	for line in fasta:
  		if start_seq not in line:
  			outfile.write(line)
  		else:
  			if outfile:
  				outfile.close()
  			outfile, i = next(split_f)
  			outfile.write(line)
  
  outfile.close()
  
subject: Add script to split HMP fasta into multiple files