bin/filter-bash-environment.py

   1 #!/usr/bin/env python
   2 # Copyright 1999-2007 Gentoo Foundation
   3 # Distributed under the terms of the GNU General Public License v2
   4 # $Id$
   5
   6 import os, re, sys
   7
   8 egrep_compat_map = {
   9         "[:alnum:]" : r'\w',
  10         "[:digit:]" : r'\d',
  11         "[:space:]" : r'\s',
  12 }
  13
  14 here_doc_re = re.compile(r'.*\s<<[-]?(\w+)$')
  15
  16 def compile_egrep_pattern(s):
  17         for k, v in egrep_compat_map.iteritems():
  18                 s = s.replace(k, v)
  19         return re.compile(s)
  20
  21 def filter_bash_environment(pattern, file_in, file_out):
  22         here_doc_delim = None
  23         for line in file_in:
  24                 if here_doc_delim is not None:
  25                         if here_doc_delim.match(line):
  26                                 here_doc_delim = None
  27                         file_out.write(line)
  28                         continue
  29                 here_doc = here_doc_re.match(line)
  30                 if here_doc is not None:
  31                         here_doc_delim = re.compile("^%s$" % here_doc.group(1))
  32                         file_out.write(line)
  33                         continue
  34                 if pattern.match(line) is None:
  35                         file_out.write(line)
  36
  37 if __name__ == "__main__":
  38         description = "Filter out any lines that match a given PATTERN " + \
  39                 "while leaving bash here-documents intact. The PATTERN should " + \
  40                 "use python regular expression syntax but [:space:] and " + \
  41                 "[:alnum:] character classes will be automatically translated " + \
  42                 "for compatibility with egrep syntax."
  43         usage = "usage: %s PATTERN" % os.path.basename(sys.argv[0])
  44         from optparse import OptionParser
  45         parser = OptionParser(description=description, usage=usage)
  46         options, args = parser.parse_args(sys.argv[1:])
  47         if len(args) != 1:
  48                 parser.error("Missing required PATTERN argument.")
  49         file_in = sys.stdin
  50         file_out = sys.stdout
  51         filter_bash_environment(
  52                 compile_egrep_pattern(args[0]), file_in, file_out)
  53         file_out.flush()