#!/usr/bin/env python
import sys
import re
import itertools


def readfile(filename): 

	f = file(filename)
	name=filename.replace('fq', 'fa').replace('fastq','fasta')
	f2 = open(name,'w')
	i=0
	
	with open(filename, 'r') as f:
		lines = f.readlines()
		for line in itertools.islice(lines, 0, None, 4):
			line=line.replace(line[0],">")
			f2.write(line)
			f2.write(lines[i+1])
			i+=4
		
	f2.close()



if len(sys.argv) < 2: 
	print ('no argument')
	sys.exit()
if sys.argv[1].startswith('--'):
	option = sys.argv[1][2:] 
	if option == 'version': 
		print ('Version 0.2')
	elif option == 'help':
		print ("input a '.fq' or '.fastq' file, output save to '.fa'")
	else:
		print ('only --version --help can be used')
		sys.exit()
else:
		readfile(sys.argv[1])
