#!/usr/bin/env python3

import sys
import os

def setprefix(dir):
  with open('conf-home') as f:
    lines = f.readlines()
  with open('conf-home.tmp','w') as g:
    g.write(dir+'\n')
    for line in lines[1:]:
      g.write(line)
  os.rename('conf-home.tmp','conf-home')

for arg in sys.argv[1:]:
  if arg.startswith('--prefix='):
    setprefix(arg[len('--prefix='):])
  else:
    raise Exception(f'unrecognized argument {arg}')
