Regular Expression Trouble

Martin McCormick martin at
Wed Aug 27 03:12:21 UTC 2008

I am trying to isolate only the MAC addresses that appear in
dhcpd logs.
For anyone who is interested, the sed construct that should do
this looks like:

 sed 's/.*\([[ your regular expression ]]\).*/\1/' 

The \1 tells sed to only print what matched and skip all the rest.

	I am doing something wrong with the regular expression
that is supposed to recognise a MAC address. MAC addresses look
like 5 pairs of hex digits followed by :'s and then a 6TH pair
to end the string.

	I have tried:


Sorry. It won't all fit on a line, but there should be a string
of 5 pairs and the : and then the 6TH pair followed by the
closing ] so the expression ends with ]]

One should also be able to put:


Any ideas as to what else I can try?

What happens is I get single characters per line that look like
the first or maybe the last character in that line, but
certainly nothing useful or nothing that remotely looks like a
MAC address.

	Any ideas as to what's wrong with the regular

	Many thanks.

Martin McCormick WB5AGZ  Stillwater, OK 
Systems Engineer
OSU Information Technology Department Telecommunications Services Group

More information about the freebsd-questions mailing list