How to add 100 spaces at end of each line of a file in Unix

Question

I have a file which is supposed to contain 200 characters in each line. I received a source file with only 100 characters in each line. I need to add 100 extra white spaces

Answer 1

With awk

awk '{printf "%s%100s\n", $0, ""}' file.dat

$0 refers to the entire line.