I wrote this answer in this challenge using Vim script. I think I was really creative and got very proud of my solution.
But I am not so sure if this is legal because this program does not print its output to
stdout but opens a Vim session with the output of the program.
This command will run the Vim script program I posted:
$ echo "This is a test line!" | vim - -c 'nm Q vEUWvEuWQ|norm Q'
This will open up Vim displaying this:
THIS is A test LINE! ~ ~ ~ ~ ~
I personally think that this is legal because it does display the correct solution but I am not sure if it counts because the result is displayed within Vim and not printed to
I am new to codegolf so I would like to hear from you if I can post more solutions like this to other programs.
out=$(mktemp) ; vim - -c "$(<"$1")"'<Esc><Esc><Esc>:wq "$out"<CR>' ; cat "$out" ; rm "$out"! That should solve your problem for future challenges. \$\endgroup\$