Forums Scripts & Popups How to ignore text that starts with X whitespace?

Try $regex($rawmsg,\s{15})

That finds long stretch anywhere within the message, not just the front.
Inside the ON TEXT event, you can see the ASCII values contents of $rawmsg with:

bset -ta &bvar 1 $rawmsg
echo -s $bvar(&bvar,1-)

I didn't expect to see colons in a hostname, so i guess the next part is to look for the first occurence of $chan followed by space then by colon.