How to add line numbers to a text file?

[Chip Salzenberg]

For line numbering, the SVID includes a little-known, seldom-used
utility called "nl" (number lines).  For interactive or short-lived
scripts, I use "nl -ba" for line numbering.  Otherwise, I tend to
write a Perl script to do the whole job.  :-)
-- 
Chip Salzenberg at Teltronics/TCT     <chip at tct.uucp>, <uunet!pdn!tct!chip>
      "I'm really sorry I feel this need to insult some people..."
            -- John F. Haugh II    (He thinks HE'S sorry?)