#! /usr/local/bin/perl

# reads in one file, and splits that file into smaller files,
#    the split points being indicated in the input file by 
#    "####begin filename"; e.g. if our input file name is x
#     and is 100 lines long, then if we insert "####begin y"
#     and "####begin z" before the 1st and 35th lines of x,
#     then running this perl script on x will produce new files
#     y and z, consisting of the first 34 and last 66 lines of x,
#     respectively

   #  open the file specified in the first command-line argument
   #     fails, then print the error message and exit
   open(INFILE,@ARGV[0]) || die "Can't open $ARGV[0]\n";

#  while there are still lines left to read from the file do
   while (<INFILE>)  {
      # split the input line, $_, into the "tokens" which were
      #    separated by spaces in the input; the tokens will be
      #    accessible as @_[0], @_[1] etc.
      split;
      # do a vi-editor-style search of the input line for the
      #    string "####begin", and if found, then open the 
      #    next new file; otherwise continue printing to the
      #    current new file
      if (/####begin/)  {open(OUTFILE,">".@_[1])}
      else {print OUTFILE $_};
   }