Hello f77coder,

I’ve always thought the regex in perlfaq5#How can I output my numbers with commas added? was pretty cool; so here it is in a one-liner:

16:56 >perl -wE "say s/(^[-+]?\d+?(?=(?>(?:\d{3})+)(?!\d))|\G\d{3}(?=\
+d))/$1,/gr for @ARGV;" 1234567 987654321098765
1,234,567
987,654,321,098,765

16:56 >
[download]

(The FAQ entry also has a commented version.)

Hope that helps,