Okay I might not have been clear. Why, in with any option checked, is it adding \<. Is that a regex command that I just don't know? The only time i've seen \< in a reged it meant a literal < not something special.

Previous \<, \>, \b indicates boundry. \< is beginning of word, \> is end of word. \b indicates either boundry.
if u just put '<' in regex, it means character '<', nothing special.

e.g. /\<hell/ will only match such string/word like 'hello', 'hell' but not 'shell'

however, i seldom use word anchor. (but maybe someone else does) <\em>

I hold this statement for a while. No argument on this. I suspend these anchors ( \< , \> ) and just use \b instead. I'll be more careful next time. Sorry everyone. This information actually referred to unreliable / wrong sources. Thanks for all feedbacks.

Did you test your claim at all?

use strict;
use warnings;

while (<DATA>) {
    chomp;
    my $matched = /\<hell/ ? 'yes' : 'no';
    print "/\\<hell/ matches '$_'? $matched\n"
}

__DATA__
shell
hell
this is hell
this is hellish
this is <hell
this is <hellish
some shells are bad
[download]

When run, this prints

Q:\>perl -w tmp.pl
'shell' matches? no
'hell' matches? no
'this is hell' matches? no
'this is hellish' matches? no
'this is <hell' matches? yes
'this is <hellish' matches? yes
'some shells are bad' matches? no
[download]

Please read perlre before making such claims.