diff --git a/apply-patch.sh b/apply-patch.sh
index c8e2ddd..63fc1d3 100755
--- a/apply-patch.sh
+++ b/apply-patch.sh
@@ -1,8 +1,7 @@
 #!/usr/bin/env bash
 
 usage() {
-    script=`basename $0`
-    echo "USAGE: $script AOSP-SRC [TAG]"
+    echo "USAGE: $(basename "$0") AOSP-SRC [TAG]"
     exit 1
 }
 
@@ -11,24 +10,26 @@ usage() {
 src=$1
 tag=$2
 
-if [ -z "$tag" ]; then
+if [[ -z $tag ]]; then
     echo "detect AOSP tag from manifest"
-    tag=`grep revision $src/.repo/manifests/default.xml | cut -d\" -f 2 | cut -d/ -f 3`
+    tag=$(basename "$(xmllint --xpath "string(/manifest/default/@revision)" "$src"/.repo/manifests/default.xml)")
 fi
 
 echo "===== AOSP SRC: $src"
 echo "===== AOSP TAG: $tag"
 
-patch_dir=$(dirname $(realpath $0))/$tag
-if [ ! -d $patch_dir ];then
+patch_dir=$(dirname "$(realpath "$0")")/$tag
+if [[ ! -d $patch_dir ]]; then
     echo "patches for $tag not exist"
     exit 1
 fi
 
-cd $patch_dir
-for p in `find * -links 2`
+cd "$patch_dir" || exit 1
+while read -r p
 do
+    [[ $(find "$patch_dir/$p" -maxdepth 1 -name '*.patch' 2> /dev/null | wc -l) -eq 0 ]] && continue
+
     echo
     echo "process project: $p"
-    git -C $src/$p am --reject $patch_dir/$p/* || echo "*****[ERROR]***** apply failed: $p"
-done
+    git -C "$src/$p" am --reject "$patch_dir/$p"/* || echo "*****[ERROR]***** apply failed: $p"
+done < <(find -- * -type d)