Why does "1" in awk print the current line?

awk

Solution

In `awk`,

Since `1` always evaluates to true, it performs default operation `{print $0}`, hence prints the current line stored in `$0`

So, `awk '$2=="no"{$3="N/A"}1' file` is equivalent to and shorthand of

awk '$2=="no"{$3="N/A"} {print $0}' file

Again `$0` is default argument to print, so you could also write

awk '$2=="no"{$3="N/A"} {print}' file

In-fact you could also use any non-zero number or any condition which always evaluates to true in place of 1

Problem

In this answer, ``` awk '$2=="no"{$3="N/A"}1' file ``` was accepted. Note the `1` at the end of the AWK script. In the comments, the author of the answer said [1 is] a cryptic way to display the current line. I'm puzzled. How does that work?

Original source