blob: b64420645ede1eaf7f49a096f1896d7bc20b5897 [file] [log] [blame]
Guido van Rossumee60eb11998-08-12 17:47:52 +00001#! /usr/bin/env python
2
3"""Reverse grep.
4
5Usage: rgrep [-i] pattern file
6"""
7
8import sys
9import re
Guido van Rossumee60eb11998-08-12 17:47:52 +000010import getopt
11
12def main():
13 bufsize = 64*1024
14 reflags = 0
15 opts, args = getopt.getopt(sys.argv[1:], "i")
16 for o, a in opts:
17 if o == '-i':
18 reflags = reflags | re.IGNORECASE
19 if len(args) < 2:
20 usage("not enough arguments")
21 if len(args) > 2:
22 usage("exactly one file argument required")
23 pattern, filename = args
24 try:
25 prog = re.compile(pattern, reflags)
26 except re.error, msg:
27 usage("error in regular expression: %s" % str(msg))
28 try:
29 f = open(filename)
30 except IOError, msg:
31 usage("can't open %s: %s" % (repr(filename), str(msg)), 1)
32 f.seek(0, 2)
33 pos = f.tell()
34 leftover = None
35 while pos > 0:
36 size = min(pos, bufsize)
37 pos = pos - size
38 f.seek(pos)
39 buffer = f.read(size)
Walter Dörwaldaaab30e2002-09-11 20:36:02 +000040 lines = buffer.split("\n")
Guido van Rossumee60eb11998-08-12 17:47:52 +000041 del buffer
42 if leftover is None:
43 if not lines[-1]:
44 del lines[-1]
45 else:
46 lines[-1] = lines[-1] + leftover
47 if pos > 0:
48 leftover = lines[0]
49 del lines[0]
50 else:
51 leftover = None
52 lines.reverse()
53 for line in lines:
54 if prog.search(line):
55 print line
56
57def usage(msg, code=2):
58 sys.stdout = sys.stderr
59 print msg
60 print __doc__
61 sys.exit(code)
62
63if __name__ == '__main__':
64 main()