a small utility for repeatedly (and interactively) running grep on the same file

igrep.py

#!/usr/bin/env python

import readline
import os
import sys
import re

if len(sys.argv) == 1:
    print >> sys.stderr, "Usage: igrep[.py] file1 [file2 ...]"
    print >> sys.stderr, "At the prompt, enter a search term to be searched in the specified file(s)."
    print >> sys.stderr, "As a shortcut, you can search for the n-th field with the search term $n"
    print >> sys.stderr, "(starting with $1)."
    print >> sys.stderr, ""
    print >> sys.stderr, "To exit, press return or CTRL+D."
    sys.exit()


histfile = os.path.join(os.environ["HOME"], ".igrephist")
try:
    readline.read_history_file(histfile)
except IOError:
    pass

import atexit
atexit.register(readline.write_history_file, histfile)

try:
    line = last_result = ""

    while True:
        s = raw_input('> ')
        
        # don't search for whitespace
        if s and not s.strip(): continue
        
        # break: empty query
        if not s: break
        
        # shortcut: searching for n-th field of last result with $n
        m = re.match(r"^\$(\d+)$", s)
        if m:
            group = int(m.group(1)) - 1
            fields = last_result.split("\t")
            if len(fields) == 1:        
                fields = last_result.split()
            
            if len(fields) <= group: continue
            
            s = fields[group]
            
        # run grep, saving last line
        for line in os.popen("grep -i --color=always %s %s " % (s, " ".join(sys.argv[1:])) ):
            print line,
            
        last_result = re.sub(r"\033\[((\d+;)*\d+m|K)", "", line).strip()
            
            
except EOFError: 
    print