Bash script that copies the file in first argument to a new copy with current date and time as extension

jbc

#!/bin/bash
# Copies the file in first argument to a new copy with current date and time as extension. I usually create a backup copy of any file I will tamper to easily revert back to the old one.
# Usage:
# $jbc test.txt
# Copies test.txt into test.txt.yymmdd_HHMMSS, for instance test.txt.210704_112158
# Put in /usr/bin as jbc (just backup copy)
# Do chmod +x /usr/bin/jbc to make it executable
if [ -z "$1" ]
then
    echo "Missing argument"
else
    d=$(date +%y%m%d_%H%M%S)
    echo "Copying $1 to $1.$d..."
    cp $1 $1.$d
fi