Question

I would like to delete the space between lines in a text file using awk. How can I do this with awk?

abcd

abcd

abcd

The desired output would be

abcd
abcd
abcd

Answer 1

awk 'NF' data.txt

will print out only non-blank lines from file data.txt. It works by only printing lines with the number of fields (NF) that are non-zero (i.e., greater than zero)

Alternatively,

awk 'length' data.txt

works by only printing out lines with length that is non-zero (i.e., greater than 0).

There are other tools, such as sed or grep, that can do this too, but since you specifically asked for an awk solution.