quine

#!/bin/bash
set -euo pipefail #bash strict mode
[ "$#" -eq 0 ] && echo USAGE: "$0 command..." && echo && echo "IMPLEMENTATION:" && cat "$0" && echo && exit 22 #usage message for invalid number of arguments

#This bash command will quine all its arguments; that is, it will print its argument string and then evaluate it (in bash) (it would probably work in plain sh as well).
#If run with no arguments, this command would ideally "quine" (ie, print out) the file or command it is being run by (making it the cheating self-rep command) — but I couldn't figure out a way to make that possible, so it doesn't do that.

echo "$@"
echo "`$@`"