[SOLVED] How do I print every nth entry of the mth column, starting from a particular line of a file?

Issue

Consider the following data in a file file.txt:

$
$
$
FORCE   10   30   40
*        1    5    4
FORCE   11   20   22
*        2    3    0
FORCE   19   25   10
*       16   12    8
.
.
.

I want to print every 2nd element of the third column, starting from line 4, resulting in:

30
20
25

I have tried:

cat file.txt | sed 's/\|/ /' | awk 'NR%2==4 {print $3}'

However, this is not resulting in anything being printed and no errors generated either.

Solution

You might use awk checking that the row number > 3 and then check for an even row number with NR%2==0.

Note that you don't have to use cat

awk 'NR > 3 && NR%2==0 {
  print $3
}' file.txt

Output

30
20
25

Answered By - The fourth bird

Answer Checked By - Marie Seifert (WPSolving Admin)