diff --git a/spring-boot-project/spring-boot-cli/src/main/executablecontent/bin/spring b/spring-boot-project/spring-boot-cli/src/main/executablecontent/bin/spring
index 21ba6a064b..3411a395a4 100755
--- a/spring-boot-project/spring-boot-cli/src/main/executablecontent/bin/spring
+++ b/spring-boot-project/spring-boot-cli/src/main/executablecontent/bin/spring
@@ -1,9 +1,9 @@
 #!/usr/bin/env bash
 
 # OS specific support (must be 'true' or 'false').
-cygwin=false;
-darwin=false;
-case "`uname`" in
+cygwin=false
+darwin=false
+case "$(uname)" in
 	CYGWIN*)
 		cygwin=true
 		;;
@@ -18,63 +18,79 @@ case "`uname`" in
 esac
 
 # For Cygwin, ensure paths are in UNIX format before anything is touched.
-if $cygwin ; then
-	[ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+if ${cygwin} ; then
+	[ -n "${JAVA_HOME}" ] && JAVA_HOME=$(cygpath --unix "${JAVA_HOME}")
 fi
 
 # Attempt to find JAVA_HOME if not already set
 if [ -z "${JAVA_HOME}" ]; then
-	if $darwin ; then
-		[ -z "$JAVA_HOME" -a -f "/usr/libexec/java_home" ] && export JAVA_HOME=`/usr/libexec/java_home`
-		[ -z "$JAVA_HOME" -a -d "/Library/Java/Home" ] && export JAVA_HOME="/Library/Java/Home"
-		[ -z "$JAVA_HOME" -a -d "/System/Library/Frameworks/JavaVM.framework/Home" ] && export JAVA_HOME="/System/Library/Frameworks/JavaVM.framework/Home"
+	if ${darwin} ; then
+		if [[ -z "${JAVA_HOME}" && -f "/usr/libexec/java_home" ]]; then
+			JAVA_HOME=$(/usr/libexec/java_home)
+			export JAVA_HOME
+		fi
+		if [[ -z "${JAVA_HOME}" && -d "/Library/Java/Home" ]]; then
+			export JAVA_HOME="/Library/Java/Home"
+		fi
+		if [[ -z "${JAVA_HOME}" && -d "/System/Library/Frameworks/JavaVM.framework/Home" ]]; then
+			export JAVA_HOME="/System/Library/Frameworks/JavaVM.framework/Home"
+		fi
 	else
-		javaExecutable="`which javac`"
-		[ -z "$javaExecutable" -o "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ] && echo "JAVA_HOME not set and cannot find javac to deduce location, please set JAVA_HOME." && exit 1
+		javaExecutable="$(command -v javac)"
+		if [[ -z "$javaExecutable" || "$(expr "${javaExecutable}" : '\([^ ]*\)')" = "no" ]]; then
+			echo "JAVA_HOME not set and cannot find javac to deduce location, please set JAVA_HOME."
+			exit 1
+		fi
 		# readlink(1) is not available as standard on Solaris 10.
-		readLink=`which readlink`
-		[ `expr "$readLink" : '\([^ ]*\)'` = "no" ] && echo "JAVA_HOME not set and readlink not available, please set JAVA_HOME." && exit 1
-		javaExecutable="`readlink -f \"$javaExecutable\"`"
-		javaHome="`dirname \"$javaExecutable\"`"
-		javaHome=`expr "$javaHome" : '\(.*\)/bin'`
-		JAVA_HOME="$javaHome"
+		readLink="$(command -v readlink)"
+		[ "$(expr "${readLink}" : '\([^ ]*\)')" = "no" ] && {
+			echo "JAVA_HOME not set and readlink not available, please set JAVA_HOME."
+			exit 1
+		}
+		javaExecutable="$(readlink -f "${javaExecutable}")"
+		javaHome="$(dirname "${javaExecutable}")"
+		javaHome=$(expr "$javaHome" : '\(.*\)/bin')
+		JAVA_HOME="${javaHome}"
 		export JAVA_HOME
 	fi
 fi
 
 # Sanity check that we have java
 if [ ! -f "${JAVA_HOME}/bin/java" ]; then
-	echo ""
-	echo "======================================================================================================"
-	echo " Please ensure that your JAVA_HOME points to a valid Java SDK."
-	echo " You are currently pointing to:"
-	echo ""
-	echo "  ${JAVA_HOME}"
-	echo ""
-	echo " This does not seem to be valid. Please rectify and restart."
-	echo "======================================================================================================"
-	echo ""
+	cat <<-JAVA_HOME_NOT_SET_TXT
+
+	======================================================================================================
+	 Please ensure that your JAVA_HOME points to a valid Java SDK.
+	 You are currently pointing to:
+
+	  ${JAVA_HOME}
+
+	 This does not seem to be valid. Please rectify and restart.
+	======================================================================================================
+
+	JAVA_HOME_NOT_SET_TXT
 	exit 1
 fi
 
 # Attempt to find SPRING_HOME if not already set
 if [ -z "${SPRING_HOME}" ]; then
-    # Resolve links: $0 may be a link
-    PRG="$0"
-    # Need this for relative symlinks.
-    while [ -h "$PRG" ] ; do
-	    ls=`ls -ld "$PRG"`
-	    link=`expr "$ls" : '.*-> \(.*\)$'`
-	    if expr "$link" : '/.*' > /dev/null; then
-		    PRG="$link"
-	    else
-		    PRG=`dirname "$PRG"`"/$link"
-	    fi
-    done
-    SAVED="`pwd`"
-    cd "`dirname \"$PRG\"`/../" >&-
-    export SPRING_HOME="`pwd -P`"
-    cd "$SAVED" >&-
+	# Resolve links: $0 may be a link
+	PRG="$0"
+	# Need this for relative symlinks.
+	while [ -h "$PRG" ] ; do
+		ls=$(ls -ld "$PRG")
+		link=$(expr "$ls" : '.*-> \(.*\)$')
+		if expr "$link" : '/.*' > /dev/null; then
+			PRG="$link"
+		else
+			PRG=$(dirname "$PRG")"/$link"
+		fi
+	done
+	SAVED="$(pwd)"
+	cd "$(dirname "${PRG}")/../" >&- || exit 1
+	SPRING_HOME="$(pwd -P)"
+	export SPRING_HOME
+	cd "$SAVED" >&- || exit 1
 fi
 
 if [ ! -d "${SPRING_HOME}" ]; then
@@ -84,16 +100,17 @@ if [ ! -d "${SPRING_HOME}" ]; then
 fi
 
 CLASSPATH=.:${SPRING_HOME}/bin
-if [ -d ${SPRING_HOME}/ext ]; then
+if [ -d "${SPRING_HOME}/ext" ]; then
 	CLASSPATH=$CLASSPATH:${SPRING_HOME}/ext
 fi
-for f in ${SPRING_HOME}/lib/*; do
+for f in "${SPRING_HOME}"/lib/*; do
 	CLASSPATH=$CLASSPATH:$f
 done
 
 if $cygwin; then
-	SPRING_HOME=`cygpath --path --mixed "$SPRING_HOME"`
-	CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+	SPRING_HOME=$(cygpath --path --mixed "$SPRING_HOME")
+	CLASSPATH=$(cygpath --path --mixed "$CLASSPATH")
 fi
 
-"${JAVA_HOME}/bin/java" ${JAVA_OPTS} -cp "$CLASSPATH" org.springframework.boot.loader.JarLauncher "$@"
+IFS=" " read -r -a javaOpts <<< "$JAVA_OPTS"
+"${JAVA_HOME}/bin/java" "${javaOpts[@]}" -cp "$CLASSPATH" org.springframework.boot.loader.JarLauncher "$@"
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