Displaying only data matching a pattern?

[Michael ODonnell]

Ben wrote:

>  sed s/.*:\([[:xdigit:]]*\)\\.*/\1/

That looks good to me, though I assume he meant to show that
expression in single quotes.  Also, I can't remember if those
character class notations count as Extended Regular Expressions
but, if so, some versions of sed might want something like -r
on the command line to enable their use.