sed: Select Last/First/Section in output.

#Select first line
seq 1 4 | sed -e '$!d'
seq 1 4 | tail -1

#Select last line
seq 1 4 | sed '1!d'
seq 1 4 | head -1

#select lines 2-3
seq 1 4 | sed '2,3!d'

#http://linuxcommando.blogspot.com/2008/03/using-sed-to-extract-lines-in-text-file.html