diff --git a/plugins.sh b/plugins.sh
index 027c382..9b08ddb 100755
--- a/plugins.sh
+++ b/plugins.sh
@@ -31,7 +31,7 @@
     exit 1
 else
     JENKINS_INPUT_JOB_LIST=$1
-    if [ ! -f $JENKINS_INPUT_JOB_LIST ]
+    if [ ! -f "$JENKINS_INPUT_JOB_LIST" ]
     then
         echo "ERROR File not found: $JENKINS_INPUT_JOB_LIST"
         exit 1
@@ -40,7 +40,7 @@
 
 # the war includes a # of plugins, to make the build efficient filter out
 # the plugins so we dont install 2x - there about 17!
-if [ -d $JENKINS_HOME ]
+if [ -d "$JENKINS_HOME" ]
 then
     TEMP_ALREADY_INSTALLED=$JENKINS_HOME/preinstalled.plugins.$$.txt
 else
@@ -49,33 +49,31 @@
 fi
 
 JENKINS_PLUGINS_DIR=/var/jenkins_home/plugins
-if [ -d $JENKINS_PLUGINS_DIR ]
+if [ -d "$JENKINS_PLUGINS_DIR" ]
 then
     echo "Analyzing: $JENKINS_PLUGINS_DIR"
-    for i in `ls -pd1 $JENKINS_PLUGINS_DIR/*|egrep '\/$'`
-    do
-        JENKINS_PLUGIN=`basename $i`
-        JENKINS_PLUGIN_VER=`egrep -i Plugin-Version "$i/META-INF/MANIFEST.MF"|cut -d\: -f2|sed 's/ //'`
+    for i in "$JENKINS_PLUGINS_DIR"/*/; do
+        JENKINS_PLUGIN=$(basename "$i")
+        JENKINS_PLUGIN_VER=$(egrep -i Plugin-Version "$i/META-INF/MANIFEST.MF"|cut -d: -f2|sed 's/ //')
         echo "$JENKINS_PLUGIN:$JENKINS_PLUGIN_VER"
-    done > $TEMP_ALREADY_INSTALLED
+    done >"$TEMP_ALREADY_INSTALLED"
 else
     JENKINS_WAR=/usr/share/jenkins/jenkins.war
-    if [ -f $JENKINS_WAR ]
+    if [ -f "$JENKINS_WAR" ]
     then
         echo "Analyzing war: $JENKINS_WAR"
         TEMP_PLUGIN_DIR=/tmp/plugintemp.$$
-        for i in `jar tf $JENKINS_WAR | egrep '[^detached-]plugins.*\..pi' | sort`
-        do
-            rm -fr $TEMP_PLUGIN_DIR
-            mkdir -p $TEMP_PLUGIN_DIR
-            PLUGIN=`basename $i|cut -f1 -d'.'`
-            (cd $TEMP_PLUGIN_DIR;jar xf $JENKINS_WAR "$i";jar xvf $TEMP_PLUGIN_DIR/$i META-INF/MANIFEST.MF >/dev/null 2>&1)
-            VER=`egrep -i Plugin-Version "$TEMP_PLUGIN_DIR/META-INF/MANIFEST.MF"|cut -d\: -f2|sed 's/ //'`
+        while read -r i <&3; do
+            rm -fr "$TEMP_PLUGIN_DIR"
+            mkdir -p "$TEMP_PLUGIN_DIR"
+            PLUGIN=$(basename "$i"|cut -f1 -d'.')
+            (cd "$TEMP_PLUGIN_DIR" || exit; jar xf "$JENKINS_WAR" "$i"; jar xvf "$TEMP_PLUGIN_DIR/$i" META-INF/MANIFEST.MF >/dev/null 2>&1)
+            VER=$(egrep -i Plugin-Version "$TEMP_PLUGIN_DIR/META-INF/MANIFEST.MF"|cut -d: -f2|sed 's/ //')
             echo "$PLUGIN:$VER"
-        done > $TEMP_ALREADY_INSTALLED
-        rm -fr $TEMP_PLUGIN_DIR
+        done 3< <(jar tf "$JENKINS_WAR" | egrep '[^detached-]plugins.*\..pi' | sort) > "$TEMP_ALREADY_INSTALLED"
+        rm -fr "$TEMP_PLUGIN_DIR"
     else
-        rm -f $TEMP_ALREADY_INSTALLED
+        rm -f "$TEMP_ALREADY_INSTALLED"
         echo "ERROR file not found: $JENKINS_WAR"
         exit 1
     fi
@@ -84,30 +82,30 @@
 REF=/usr/share/jenkins/ref/plugins
 mkdir -p $REF
 COUNT_PLUGINS_INSTALLED=0
-while read spec || [ -n "$spec" ]; do
+while read -r spec || [ -n "$spec" ]; do
 
     plugin=(${spec//:/ });
     [[ ${plugin[0]} =~ ^# ]] && continue
-    [[ ${plugin[0]} =~ ^\s*$ ]] && continue
+    [[ ${plugin[0]} =~ ^[[:space:]]*$ ]] && continue
     [[ -z ${plugin[1]} ]] && plugin[1]="latest"
 
     if [ -z "$JENKINS_UC_DOWNLOAD" ]; then
       JENKINS_UC_DOWNLOAD=$JENKINS_UC/download
     fi
 
-    if ! grep -q "${plugin[0]}:${plugin[1]}" $TEMP_ALREADY_INSTALLED
+    if ! grep -q "${plugin[0]}:${plugin[1]}" "$TEMP_ALREADY_INSTALLED"
     then
         echo "Downloading ${plugin[0]}:${plugin[1]}"
-        curl --retry 3 --retry-delay 5 -sSL -f ${JENKINS_UC_DOWNLOAD}/plugins/${plugin[0]}/${plugin[1]}/${plugin[0]}.hpi -o $REF/${plugin[0]}.jpi
-        unzip -qqt $REF/${plugin[0]}.jpi
-        COUNT_PLUGINS_INSTALLED=`expr $COUNT_PLUGINS_INSTALLED + 1`
+        curl --retry 3 --retry-delay 5 -sSL -f "${JENKINS_UC_DOWNLOAD}/plugins/${plugin[0]}/${plugin[1]}/${plugin[0]}.hpi" -o "$REF/${plugin[0]}.jpi"
+        unzip -qqt "$REF/${plugin[0]}.jpi"
+        (( COUNT_PLUGINS_INSTALLED += 1 ))
     else
         echo "  ... skipping already installed:  ${plugin[0]}:${plugin[1]}"
     fi
-done  < $JENKINS_INPUT_JOB_LIST
+done  < "$JENKINS_INPUT_JOB_LIST"
 
 echo "---------------------------------------------------"
-if [ $COUNT_PLUGINS_INSTALLED -gt 0 ]
+if (( "$COUNT_PLUGINS_INSTALLED" > 0 ))
 then
     echo "INFO: Successfully installed $COUNT_PLUGINS_INSTALLED plugins."
 
@@ -122,5 +120,5 @@
 echo "---------------------------------------------------"
 
 #cleanup
-rm $TEMP_ALREADY_INSTALLED
+rm "$TEMP_ALREADY_INSTALLED"
 exit 0