Apply shellcheck recommendations

res/util/script-addon.sh

@@ -62,7 +62,7 @@ case "$1" in
     save_files | translate_path | while read -r object; do
       [ "$object" ] && [ -e "$S/$object" ] || continue;
       find "$S/$object" -type f | while read -r file; do
-        file="${file#$S/}";
+        file="${file#"$S/"}";
         backup_file "$S/$file";
         log "BACKUPER: Object backed up ($file)";
       done;
@@ -74,7 +74,7 @@ case "$1" in
     save_files | translate_path | while read -r object; do
       [ "$object" ] && [ -e "$C/$S/$object" ] || continue;
       find "$C/$S/$object" -type f | while read -r file; do
-        file="${file#$C/$S/}";
+        file="${file#"$C/$S/"}";
         restore_file "$S/$file";
         log "RESTORER: Object restored ($file)";
       done;

src/META-INF/com/google/android/update-binary

@@ -73,10 +73,6 @@ abort() {
   exit 1;
 }
 
-ismntpoint() {
-  mount | grep -q " on $1 ";
-}
-
 fstab_getmount() {
   grep -v "^#" /etc/recovery.fstab | grep "[[:blank:]]$1[[:blank:]]" | tail -n1 | tr -s "[:blank:]" " " | cut -d" " -f1;
 }
@@ -186,7 +182,7 @@ case "$(basename "$zipfile" | tr 'A-Z' 'a-z')" in
   ;;
 esac;
 
-abi="$(file_getprop $sysroot/system/build.prop ro.product.cpu.abi)";
+abi="$(file_getprop "$sysroot/system/build.prop" ro.product.cpu.abi)";
 case "$abi" in
   arm64*)
     arch=arm64;
@@ -217,7 +213,7 @@ case "$abi" in
   ;;
 esac;
 
-sdk="$(file_getprop $sysroot/system/build.prop ro.build.version.sdk)";
+sdk="$(file_getprop "$sysroot/system/build.prop" ro.build.version.sdk)";
 [ "$sdk" ] || abort "Could not find SDK";
 [ "$sdk" -gt 0 ] || abort "Could not recognise SDK: $sdk";