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

Answer 1

It looks like you are comfortable using vim, but here is a pure Bash/simple-sed solution in case you need to do it from the command line (note the 63 spaces in the sed substitution):

$ sed 's/$/                                                               /' yourFile.txt |cut -c 1-63