#!/usr/bin/perl -w
# Filename:      grepc
# Purpose:       grep for pattern and cut it
# Authors:       Olaf Klischat <klischat@cs.tu-berlin.de>
# Bug-Reports:   see http://grml.org/bugs/
################################################################################

################################################################################
# Usage-Examples taken from:
# http://groups.google.de/groups?selm=87acw742ea.fsf%40swangoose.isst.fhg.de

# get ipaddress of interface ppp0:
# $ ifconfig ppp0 | grepc 'inet addr:(.*?)\s'

# list all debian packages which have dependency on a given package
# $ apt-cache showpkg perl-tk | grepc '(.*?),perl-tk'

# list all files which have been changed in comparison to the
# cvs repository:
# $ cvs diff 2>/dev/null | grepc '^RCS file: (.*?),v$'

# get environment variable of a specific process:
# $ grepc 'PATH=(.*?)\0' </proc/<pid>/environ

# list destination ports of iptables lol:
# $ </var/log/messages grepc 'DPT=(.*?) '

# get debian packages on host1, download them on host2:
# host1:$ apt-get install --yes --force-yes --print-uris gnome >uris.txt
# host2:$ <uris.txt grepc "^'(.*?)'" | xargs -l ncftpget

# list all directories containing apache-java source:
# $ find . -path '*org/apache/*.java' | grepc '^(.*?)/org/apache' | sort | uniq
################################################################################

my $re = shift or die "usage: grepc <perl regexp containing a capture buffer>\n";

$re = eval { qr/$re/ } or die "invalid regexp: $@";

while (<>) {
    if (/$re/) {
        print "$1\n";
    }
}

## END OF FILE #################################################################