diff --git a/jenkins.sh b/jenkins.sh
index 97d7fcc..eeed64b 100755
--- a/jenkins.sh
+++ b/jenkins.sh
@@ -7,22 +7,22 @@
 # Don't override, as this is just a reference setup, and use from UI 
 # can then change this, upgrade plugins, etc.
 copy_reference_file() {
-	f=${1%/} 
-	echo "$f" >> $COPY_REFERENCE_FILE_LOG
-    rel=${f:23}
-    dir=$(dirname ${f})
-    echo " $f -> $rel" >> $COPY_REFERENCE_FILE_LOG
+	f="${1%/}"
+	echo "$f" >> "$COPY_REFERENCE_FILE_LOG"
+    rel="${f:23}"
+    dir="$(dirname ${f})"
+    echo " $f -> $rel" >> "$COPY_REFERENCE_FILE_LOG"
 	if [[ ! -e /var/jenkins_home/${rel} ]] 
 	then
-		echo "copy $rel to JENKINS_HOME" >> $COPY_REFERENCE_FILE_LOG
-		mkdir -p /var/jenkins_home/${dir:23}
-		cp -r /usr/share/jenkins/ref/${rel} /var/jenkins_home/${rel};
+		echo "copy $rel to JENKINS_HOME" >> "$COPY_REFERENCE_FILE_LOG"
+		mkdir -p "/var/jenkins_home/${dir:23}"
+		cp -r "/usr/share/jenkins/ref/${rel}" "/var/jenkins_home/${rel}";
 		# pin plugins on initial copy
-		[[ ${rel} == plugins/*.jpi ]] && touch /var/jenkins_home/${rel}.pinned
+		[[ ${rel} == plugins/*.jpi ]] && touch "/var/jenkins_home/${rel}.pinned"
 	fi; 
 }
 export -f copy_reference_file
-echo "--- Copying files at $(date)" >> $COPY_REFERENCE_FILE_LOG
+echo "--- Copying files at $(date)" >> "$COPY_REFERENCE_FILE_LOG"
 find /usr/share/jenkins/ref/ -type f -exec bash -c "copy_reference_file '{}'" \;
 
 # if `docker run` first argument start with `--` the user is passing jenkins launcher arguments