@@ -27,8 +27,8 @@ while true; do

 	case "$1" in

 		-d|--dir) dir="$2" ; shift 2 ;;

 		-t|--tag) tag="$2" ; shift 2 ;;

-		-c|--compression) compression="$2" ; shift 2 ;;

-		-C|--no-compression) compression="none" ; shift 1 ;;

+		--compression)    compression="$2"   ; shift 2 ;;

+		--no-compression) compression="none" ; shift 1 ;;

 		-h|--help) usage ;;

 		--) shift ; break ;;

 	esac

@@ -38,17 +38,12 @@ script="$1"

 [ "$script" ] || usage

 shift

-if [ "$compression" == "auto" ] || [ -z "$compression" ]

+if [ "$compression" == 'auto' ] || [ -z "$compression" ]

 then

-	compression="xz"

+    compression='xz'

 fi

-if [ "$compression" == "none" ]

-then

-	compression=""

-else

-	compression=".${compression}"

-fi

+[ "$compression" == 'none' ] && compression=''

 if [ ! -x "$scriptDir/$script" ]; then

 	echo >&2 "error: $script does not exist or is not executable"

@@ -86,7 +81,7 @@ nameserver 8.8.8.8

 nameserver 8.8.4.4

 EOF

-tarFile="$dir/rootfs.tar${compression}"

+tarFile="$dir/rootfs.tar${compression:+.$compression}"

 touch "$tarFile"

 (

@@ -97,7 +92,7 @@ touch "$tarFile"

 echo >&2 "+ cat > '$dir/Dockerfile'"

 cat > "$dir/Dockerfile" <<EOF

 FROM scratch

-ADD $tarFile /

+ADD $(basename "$tarFile") /

 EOF

 # if our generated image has a decent shell, let's set a default command