busybox/applets_sh/mim

#!/bin/sh
MIMFILE="Mimfile"
if [ $# -ge 2 ] && [ "$1" = "-f" ]
then
	MIMFILE="$2"
	shift 2
fi
exec <"$MIMFILE" || exit 1
{
	INCASE=false
	while read -r REPLY
	do
		case $REPLY in
		*:)
			if ! $INCASE
			then
				printf '[ $# -eq 0 ] && set -- "%s"
TARGET="$1"
shift
case "$TARGET" in
' "${REPLY%:}"
			else
				printf ';;\n'
			fi
			printf '%s)\n' "${REPLY%:}"
			INCASE=true
			;;
		"") ;;
		*) printf '%s\n' "${REPLY##[ 	]}";;
		esac
	done
	$INCASE && printf ';;\n'
	printf '*)
echo "Unknown command $TARGET"
exit 1
;;
esac
'
} | sh -s "$@"