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

If you want to have fixed n chars per line (don't trust the input file has exact m chars per line) follow this. For the input file with varying number of chars per line:

$ cat file
1
12
123
1234
12345

extend to 10 chars per line.

$ awk '{printf "%-10s\n", $0}' file | cat -e

1         $
12        $
123       $
1234      $
12345     $

Obviously change 10 to 200 in your script. Here $ shows end of line, it's not there as a character. You don't need cat -e, here just to show the line is extended.