use strict;
use warnings;
use Data::Dumper ();

die "No search terms supplied!" unless @ARGV;
my @words = @ARGV;

my $text = do { local $/ = undef; <DATA> };

my $blen = 20;	# (max) chars before a matching word to take with us
my $alen = 20;	# (max) chars after a matching word to take with us
my $jlen = $blen+$alen;	# (max) chars between 2 matching words captured together

my $strwords = join "|" => map quotemeta, @words; # Words to highlight
my $rxwords = qr/\b(?i:$strwords)\b/;	# ... compiled highlight word match
my $expr = qr/\b(?!\s)(?s:.{0,$blen}$rxwords(?:.{0,$jlen}$rxwords)*.{0,$alen}(?:(?<=\s)|[^\s]*\b))/;

my $D = Data::Dumper->new(
	[[grep {s/($rxwords)/[$1]/g} $text =~ /($expr)/g]], ['matched']
)->Indent(1);
print $D->Dump();

# reformatted the DATA to look nicer in the post
__DATA__
Regular expressions have always been a weak spot for me, and
I've got a question that's got me stumped.  Here's the
problem I'm trying to solve.  I have somewhat large articles
of text (returned from a search), what I'd like to do is
capture the word and X number of words before and after it
while tagging the matching word in the captured text.  My
inital thought was to try something like this.  The problem I
have is that if there is more than one term and they overlap,
the nth term will not be annotated.  So my next thought is
lookahead/lookbehind, but they don't capture.  Is there a way
to do this with a single regex?  Is a regex even the best way
to do this?  Thanks, -Lee