#!/usr/bin/perl

#
# tok -- extract tokens from input text
#
# Like grep(1) but prints only the matching part of a line.
#
# Options:
#   -e <regex> -- regular expression to match
#   -f <fmt>   -- print matches using <fmt>
#   -1         -- print one match per format
#
use Getopt::Std;

getopts('1e:f:');

$regexp = $opt_e || shift @ARGV;

my %ec = ('n' => "\n");

if ($opt_f) {
    ($format = $opt_f) =~
	s/\\(.)/defined($ec{$1}) ? $ec{$1} : $1/ge;
}

while (<>) {
    chomp;
    next unless (@matches = m/$regexp/og);

    if ($format) {
	if ($opt_1) {
	    printf($format, $_) for @matches;
	}
	else {
	    printf($format, @matches);
	}
    }
    else {
	print join("\n", @matches, '');
    }
}