keyword coloring on terminal.

color.pl

#!/usr/bin/env perl -w
use strict;
my $kw_path = shift @ARGV;
if( !defined($kw_path) || !(-e $kw_path ) ){
    die <<"__USAGE__";
Usage:
# tail -f | ./color.pl keywords.pl

keywords are defined by ArrayRef such as:
[qw(error fail)];
__USAGE__
}
my $keywords = do $kw_path;

die "Keywords must be ARRAY reference." if !defined $keywords || ( ref($keywords) || q{} ) ne 'ARRAY';
die "You must define keywords one or more" if @$keywords == 0;

my $pattern = join '|', map{ qq{\Q$_\E} } @$keywords;
$pattern = qr/($pattern)/i;

while(<STDIN>){
    s/$pattern/\x1b[31m$1\x1b[0m/g;#red
    print;
}
__END__