age shadow script to emulate gpg {-d,-e} <file>

age.sh

#!/bin/sh -eu
# shadow script that does three things:
# - 'age -e <file>' produce an ascii armored <file>.age in the same
#   directory encrypted with the age_def_rec file
# - 'age -d <file>' decrypts the file to stdout with the age_def_id file
# - anything that's not a file or doesn't uses -e/-d flags gets sent to the
#   proper age binary location at age_bin

age_bin=/usr/bin/rage
age_def_rec="${XDG_CONFIG_HOME:-$HOME/.config}/age/recipients.txt"
age_def_id="${XDG_CONFIG_HOME:-$HOME/.config}/age/identity.txt"

if [ "$#" -ne 2 ]; then
	exec "$age_bin" "$@"
fi

if ! [ -f "$2" ]; then
	exec "$age_bin" "$@"
fi

file="$2"

case "${1%%:*}" in
	-e|--encrypt)
		exec "$age_bin" -e -R "$age_def_rec" -a -o "$file.age" "$file"
		;;
	-d|--decrypt)
		exec "$age_bin" -d -i "$age_def_id" "$file"
		;;
	*)
		exec "$age_bin" "$@"
		;;
esac