Question

How do I choose even numbered rows of a file?
I wish to select rows #2, 4, 6, etc. from a file that contains data. Can anyone help me with this?

Answer 1

An awk example (as an alternative to Mark’s sed example):

awk 'NR % 2 == 0' filename

Example:

$ cat filename
line 0
line 1
line 2
line 3
line 4
line 5
line 6
line 7
line 8

$ awk 'NR % 2 == 0' filename
line 1
line 3
line 5
line 7