Pad all lines with spaces to a fixed width in Vim or using sed, awk, etc

Question

How can I pad each line of a file to a certain width (say, 63 characters wide), padding with spaces if need be?

For now, let’s assume all lines are guaranteed to be less than 63 characters.

I use Vim and would prefer a way to do it there, where I can select the lines I wish to apply the padding to, and run some sort of a printf %63s current_line command.

However, I’m certainly open to using sed, awk, or some sort of linux tool to do the job too.

Answer 1

Vim

:%s/.*/\=printf('%-63s', submatch(0))

Answer 2

$ awk '{printf "%-63s\n", $0}' testfile > newfile

Answer 3

In Vim, I would use the following command:

:%s/$/\=repeat(' ',64-virtcol('$'))

(The use of the virtcol() function, as opposed to the col() one, is guided by the necessity to properly handle tab characters as well as multibyte non-ASCII characters that might occur in the text.)

Answer 4

Just for fun, a Perl version:

$ perl -lpe '$_ .= " " x (63 - length $_)'