| Note that this would have given a non-null value to MATCH:
| With the ".*" after "Keywords" moved to the right, it becomes greedy and
| reaches all the way to the digits, and MATCH="<space>9999".
Correction: the second ".*" would have reached not just up to the digits but
through them to the end of the line. If that regexp were matched with this
Subject: Keywords-- I have 9999 reasons to bite your nose.
or this one, which contains no digits,
Subject: Keywords, keywords, keywords all over the place!
MATCH would contain what I've indicated, all of it matched to ".*" plus null
matched to "[0-9]*".