I'm using sed to make philters. I can parse all lines using the prefix
1,$ but I'd like to avoid the first and last line from the command focus.
Is there a symbol or an expression for the last but one line ( $-1 doesn't
work) ?

sir Alex

You might try explicitly dropping the first and last lines:
sed '1,d; $,d'

Dave

+---------------------+---------------+
|nojunkm...@nospam.com| mindspring.com|
|nos...@nojunkmail.com| davegrantier@ |
+---------------------+---------------+

$ sed '$!s/:/%/g' /etc/passwd

        .  That says to match the last line, and then execute the
command shown for every line _except_ that matched line.  Getting every line
except the first _and_ the last one is a little trickier; the easiest way I
can think of is

$ sed '1{
p;d
$!s/:/%/g'

        , which does the same thing, but first prints the first line
untouched, and then deletes it from the pattern space.

        -- Sweth.

--
Sweth Chandramouli ; <sw...@sweth.net>
<a href="http://www.sweth.net/legal/disc.html">*</a>

A simpler way would be:
  sed '1b
       $!s/:/%/g'

                --Ken Pizzini