Alternative script for "apt-key add" which is deprecated in Ubuntu 20.10

apt-key-add

#!/bin/bash
# apt-key-add - Alternative script for "apt-key add" which is deprecated in Ubuntu 20.10
#
# example:
# curl -fsSL https://deb.nodesource.com/gpgkey/nodesource.gpg.key | sudo apt-key-add - nodesource
# instead of
# curl -fsSL https://deb.nodesource.com/gpgkey/nodesource.gpg.key | sudo apt-key add -
#
set -e
if [ $# -ne 2 -o $UID -ne 0 ]; then
  cat <<EOF >&2
Usage: my-apt-key-add src dest_basename

Specify - for src to use stdin as input.
The imported key filename will be "/etc/apt/trusted.gpg.d/\${dest_basename}.gpg".

This script must be executed by root.
EOF
  exit 2
fi

src="$1"
dest="/etc/apt/trusted.gpg.d/$2.gpg"
if [ -f "$dest" ]; then
  echo "Exiting without adding key since destination file $dest already exists." >&2
  exit 1
fi

gpg --no-default-keyring --keyring "gnupg-ring:$dest" --import "$src"
chmod 644 "$dest"
rm "$dest~"