libcxx/utils/cat_files.py

   1 #!/usr/bin/env python
   2 #===----------------------------------------------------------------------===##
   3 #
   4 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 # See https://llvm.org/LICENSE.txt for license information.
   6 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 #
   8 #===----------------------------------------------------------------------===##
   9
  10 from argparse import ArgumentParser
  11 import sys
  12
  13 def print_and_exit(msg):
  14     sys.stderr.write(msg + '\n')
  15     sys.exit(1)
  16
  17 def main():
  18     parser = ArgumentParser(
  19         description="Concatenate two files into a single file")
  20     parser.add_argument(
  21         '-o', '--output', dest='output', required=True,
  22         help='The output file. stdout is used if not given',
  23         type=str, action='store')
  24     parser.add_argument(
  25         'files', metavar='files',  nargs='+',
  26         help='The files to concatenate')
  27
  28     args = parser.parse_args()
  29
  30     if len(args.files) < 2:
  31         print_and_exit('fewer than 2 inputs provided')
  32     data = ''
  33     for filename in args.files:
  34         with open(filename, 'r') as f:
  35             data += f.read()
  36         if len(data) != 0 and data[-1] != '\n':
  37             data += '\n'
  38     assert len(data) > 0 and "cannot cat empty files"
  39     with open(args.output, 'w') as f:
  40         f.write(data)
  41
  42
  43 if __name__ == '__main__':
  44     main()
  45     sys.exit(0)