in reply to regex to deny characters?

Try this. 

for $w ('abd -def', 'Abcdef', 'abd_def', "abd\tdef") {
    print $w, $w =~ /^[-a-z\ ]+$/ ? 'ok' : 'not ok',$/ 
}
abd -def ok
Abcdef not ok
abd_def not ok
abd     def not ok

[download]

Use !~ to invert the match.

Okay you lot, get your wings on the left, halos on the right. It's one size fits all, and "No!", you can't have a different color.
Pick up your cloud down the end and "Yes" if you get allocated a grey one they are a bit damp under foot, but someone has to get them.
Get used to the wings fast cos its an 8 hour day...unless the Govenor calls for a cyclone or hurricane, in which case 16 hour shifts are mandatory.
Just be grateful that you arrived just as the tornado season finished. Them buggers are real work.

In Section Seekers of Perl Wisdom