Fix #11 and #15 (#17)

* Add Option to show subvolumes only

* Fix spaces in subvolumes not shown

Co-authored-by: Jesai Langenbach <j.langenbach@kdz-ws.net>

btrfs-du

@@ -29,7 +29,26 @@ bytesToHumanIEC() {
     echo "$b$d${S[$s]}"
 }
 
-LOCATION=${1:-/}
+BTRFS_OPT=""
+
+while [ ${#} -gt 0 ]; do
+  case "${1}" in
+      -h)
+          echo -en "btrfs-du [-o] <PATH_to_BTRFS-mount>\n\n"
+          echo -en "-o\t\tprint only subvolumes below specified path\n"
+          echo -en "-h\t\tprint help\n"
+          exit 0
+          ;;
+      -o)
+          BTRFS_OPT=" -o "
+          shift
+          ;;
+      *)
+        LOCATION=${1:-/}
+        shift
+        ;;
+  esac
+done
 
 # checks
 [[ ${EUID} -ne 0 ]] && {
@@ -98,9 +117,9 @@ for (( i = 0 ; i < ${#ID__[@]} ; i++ )); do
 done
 
 ## naming data
-OUT=$( btrfs subvolume list --sort=rootid "$LOCATION" | cut -d ' ' -f 2,9 )
-ID__=( $( awk '{ print $1 }' <<< "$OUT" ) )
-NAM_=( $( awk '{ print $2 }' <<< "$OUT" ) )
+OUT=$( btrfs subvolume list -t --sort=rootid ${BTRFS_OPT} "$LOCATION"| tail -n +3 )
+ID__=( $( awk -F "\t" '{ print $1 }' <<< "$OUT" ) )
+NAM_=( $( awk -F "\t" '{ print $5 }' <<< "$OUT" ) )
 
 for (( i = 0 ; i < ${#ID__[@]} ; i++ )); do
   NAME[${ID__[$i]}]=${NAM_[$i]}