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
  14 def print_and_exit(msg):
  15     sys.stderr.write(msg + "\n")
  16     sys.exit(1)
  17
  18
  19 def main():
  20     parser = ArgumentParser(description="Concatenate two files into a single file")
  21     parser.add_argument(
  22         "-o",
  23         "--output",
  24         dest="output",
  25         required=True,
  26         help="The output file. stdout is used if not given",
  27         type=str,
  28         action="store",
  29     )
  30     parser.add_argument(
  31         "files", metavar="files", nargs="+", help="The files to concatenate"
  32     )
  33
  34     args = parser.parse_args()
  35
  36     if len(args.files) < 2:
  37         print_and_exit("fewer than 2 inputs provided")
  38     data = ""
  39     for filename in args.files:
  40         with open(filename, "r") as f:
  41             data += f.read()
  42         if len(data) != 0 and data[-1] != "\n":
  43             data += "\n"
  44     assert len(data) > 0 and "cannot cat empty files"
  45     with open(args.output, "w") as f:
  46         f.write(data)
  47
  48
  49 if __name__ == "__main__":
  50     main()
  51     sys.exit(0)