diff --git a/src/Misc/externals.sh b/src/Misc/externals.sh
index 62ba9126a9..e4f7f10da8 100755
--- a/src/Misc/externals.sh
+++ b/src/Misc/externals.sh
@@ -12,8 +12,8 @@ get_abs_path() {
   echo "$(cd "$(dirname "$1")" && pwd)/$(basename "$1")"
 }
 
-LAYOUT_DIR=$(get_abs_path `dirname $0`/../../_layout)
-DOWNLOAD_DIR="$(get_abs_path `dirname $0`/../../_downloads)/netcore2x"
+LAYOUT_DIR=$(get_abs_path "$(dirname $0)/../../_layout")
+DOWNLOAD_DIR="$(get_abs_path "$(dirname $0)/../../_downloads")/netcore2x"
 
 function failed() {
    local error=${1:-Undefined error}
@@ -41,8 +41,8 @@ function acquireExternalTool() {
 
     # Check if the download already exists.
     local download_target="$DOWNLOAD_DIR/$relative_url"
-    local download_basename="$(basename $download_target)"
-    local download_dir="$(dirname $download_target)"
+    local download_basename="$(basename "$download_target")"
+    local download_dir="$(dirname "$download_target")"
 
     if [[ "$PRECACHE" != "" ]]; then
         if [ -f "$download_target" ]; then
@@ -57,7 +57,7 @@ function acquireExternalTool() {
 
             # Download from source to the partial file.
             echo "Downloading $download_source"
-            mkdir -p "$(dirname $download_target)" || checkRC 'mkdir'
+            mkdir -p "$(dirname "$download_target")" || checkRC 'mkdir'
             # curl -f Fail silently (no output at all) on HTTP errors (H)
             #      -k Allow connections to SSL sites without certs (H)
             #      -S Show error. With -s, make curl show errors when they occur
diff --git a/src/dev.sh b/src/dev.sh
index 2c09641cbd..a34966194c 100755
--- a/src/dev.sh
+++ b/src/dev.sh
@@ -6,6 +6,8 @@
 #
 ###############################################################################
 
+set -e
+
 DEV_CMD=$1
 DEV_CONFIG=$2
 
@@ -16,9 +18,9 @@ PACKAGE_DIR="$SCRIPT_DIR/../_package"
 DOTNETSDK_ROOT="$SCRIPT_DIR/../_dotnetsdk"
 DOTNETSDK_VERSION="2.1.403"
 DOTNETSDK_INSTALLDIR="$DOTNETSDK_ROOT/$DOTNETSDK_VERSION"
-AGENT_VERSION=`cat agentversion`
+AGENT_VERSION=$(cat agentversion)
 
-pushd $SCRIPT_DIR
+pushd "$SCRIPT_DIR"
 
 BUILD_CONFIG="Debug"
 if [[ "$DEV_CONFIG" == "Release" ]]; then
@@ -26,8 +28,8 @@ if [[ "$DEV_CONFIG" == "Release" ]]; then
 fi
 
 CURRENT_PLATFORM="windows"
-if [[ (`uname` == "Linux") || (`uname` == "Darwin") ]]; then
-    CURRENT_PLATFORM=`echo \`uname\` | awk '{print tolower($0)}'`
+if [[ ($(uname) == "Linux") || ($(uname) == "Darwin") ]]; then
+    CURRENT_PLATFORM=$(uname | awk '{print tolower($0)}')
 fi
 
 if [[ "$CURRENT_PLATFORM" == 'windows' ]]; then
@@ -102,44 +104,34 @@ function heading()
 {
     echo
     echo
-    echo -----------------------------------------
-    echo   ${1}
-    echo -----------------------------------------
+    echo "-----------------------------------------"
+    echo "  ${1}"
+    echo "-----------------------------------------"
 }
 
 function build ()
 {
     heading "Building ..."
+    dotnet msbuild -t:Build -p:PackageRuntime="${RUNTIME_ID}" -p:BUILDCONFIG="${BUILD_CONFIG}" -p:Version="${AGENT_VERSION}" || failed build
 
-    if [[ ("$CURRENT_PLATFORM" == "windows") ]]; then
-        dotnet msbuild //t:Build //p:PackageRuntime=${RUNTIME_ID} //p:BUILDCONFIG=${BUILD_CONFIG} //p:Version=${AGENT_VERSION} || failed build
-    else
-        dotnet msbuild /t:Build /p:PackageRuntime=${RUNTIME_ID} /p:BUILDCONFIG=${BUILD_CONFIG} /p:Version=${AGENT_VERSION} || failed build
-    fi    
-
-    mkdir -p ${LAYOUT_DIR}/bin/en-US
-    grep --invert-match '^ *"CLI-WIDTH-' ./Misc/layoutbin/en-US/strings.json > ${LAYOUT_DIR}/bin/en-US/strings.json
+    mkdir -p "${LAYOUT_DIR}/bin/en-US"
+    grep --invert-match '^ *"CLI-WIDTH-' ./Misc/layoutbin/en-US/strings.json > "${LAYOUT_DIR}/bin/en-US/strings.json"
 }
 
 function layout ()
 {
     heading "Create layout ..."
+    dotnet msbuild -t:layout -p:PackageRuntime="${RUNTIME_ID}" -p:BUILDCONFIG="${BUILD_CONFIG}" -p:Version="${AGENT_VERSION}" || failed build
 
-    if [[ ("$CURRENT_PLATFORM" == "windows") ]]; then
-        dotnet msbuild //t:layout //p:PackageRuntime=${RUNTIME_ID} //p:BUILDCONFIG=${BUILD_CONFIG} //p:Version=${AGENT_VERSION} || failed build
-    else
-        dotnet msbuild /t:layout /p:PackageRuntime=${RUNTIME_ID} /p:BUILDCONFIG=${BUILD_CONFIG} /p:Version=${AGENT_VERSION} || failed build
-    fi
-
-    mkdir -p ${LAYOUT_DIR}/bin/en-US
-    grep --invert-match '^ *"CLI-WIDTH-' ./Misc/layoutbin/en-US/strings.json > ${LAYOUT_DIR}/bin/en-US/strings.json
+    mkdir -p "${LAYOUT_DIR}/bin/en-US"
+    grep --invert-match '^ *"CLI-WIDTH-' ./Misc/layoutbin/en-US/strings.json > "${LAYOUT_DIR}/bin/en-US/strings.json"
 
     #change execution flag to allow running with sudo
     if [[ ("$CURRENT_PLATFORM" == "linux") || ("$CURRENT_PLATFORM" == "darwin") ]]; then
-        chmod +x ${LAYOUT_DIR}/bin/Agent.Listener
-        chmod +x ${LAYOUT_DIR}/bin/Agent.Worker
-        chmod +x ${LAYOUT_DIR}/bin/Agent.PluginHost
-        chmod +x ${LAYOUT_DIR}/bin/installdependencies.sh
+        chmod +x "${LAYOUT_DIR}/bin/Agent.Listener"
+        chmod +x "${LAYOUT_DIR}/bin/Agent.Worker"
+        chmod +x "${LAYOUT_DIR}/bin/Agent.PluginHost"
+        chmod +x "${LAYOUT_DIR}/bin/installdependencies.sh"
     fi
 
     heading "Setup externals folder for $RUNTIME_ID agent's layout"
@@ -156,11 +148,7 @@ function runtest ()
 
     export VSTS_AGENT_SRC_DIR=${SCRIPT_DIR}
 
-    if [[ ("$CURRENT_PLATFORM" == "windows") ]]; then
-        dotnet msbuild //t:test //p:PackageRuntime=${RUNTIME_ID} //p:BUILDCONFIG=${BUILD_CONFIG} //p:Version=${AGENT_VERSION} || failed "failed tests" 
-    else
-        dotnet msbuild /t:test /p:PackageRuntime=${RUNTIME_ID} /p:BUILDCONFIG=${BUILD_CONFIG} /p:Version=${AGENT_VERSION} || failed "failed tests" 
-    fi
+    dotnet msbuild -t:test -p:PackageRuntime="${RUNTIME_ID}" -p:BUILDCONFIG="${BUILD_CONFIG}" -p:Version="${AGENT_VERSION}" || failed "failed tests" 
 }
 
 function package ()
@@ -169,21 +157,23 @@ function package ()
         echo "You must build first.  Expecting to find ${LAYOUT_DIR}/bin"
     fi
 
-    agent_ver=`${LAYOUT_DIR}/bin/Agent.Listener --version` || failed "version"
+    agent_ver=$("${LAYOUT_DIR}/bin/Agent.Listener" --version) || failed "version"
     agent_pkg_name="vsts-agent-${RUNTIME_ID}-${agent_ver}"
 
     heading "Packaging ${agent_pkg_name}"
 
-    rm -Rf ${LAYOUT_DIR}/_diag
-    find ${LAYOUT_DIR}/bin -type f -name '*.pdb' -delete
-    mkdir -p $PACKAGE_DIR
-    pushd $PACKAGE_DIR > /dev/null
-    rm -Rf *
+    rm -Rf "${LAYOUT_DIR:?}/_diag"
+    find "${LAYOUT_DIR}/bin" -type f -name '*.pdb' -delete
+
+    mkdir -p "$PACKAGE_DIR"
+    rm -Rf "${PACKAGE_DIR:?}/*"
+
+    pushd "$PACKAGE_DIR" > /dev/null
 
     if [[ ("$CURRENT_PLATFORM" == "linux") || ("$CURRENT_PLATFORM" == "darwin") ]]; then
         tar_name="${agent_pkg_name}.tar.gz"
         echo "Creating $tar_name in ${LAYOUT_DIR}"
-        tar -czf "${tar_name}" -C ${LAYOUT_DIR} .
+        tar -czf "${tar_name}" -C "${LAYOUT_DIR}" .
     elif [[ ("$CURRENT_PLATFORM" == "windows") ]]; then
         zip_name="${agent_pkg_name}.zip"
         echo "Convert ${LAYOUT_DIR} to Windows style path"
@@ -206,19 +196,19 @@ if [[ (! -d "${DOTNETSDK_INSTALLDIR}") || (! -e "${DOTNETSDK_INSTALLDIR}/.${DOTN
     #                            \dotnet
     #                            \.1.0.x
     echo "Download dotnetsdk into ${DOTNETSDK_INSTALLDIR}"
-    rm -Rf ${DOTNETSDK_DIR}
+    rm -Rf "${DOTNETSDK_DIR}"
 
     # run dotnet-install.ps1 on windows, dotnet-install.sh on linux
     if [[ ("$CURRENT_PLATFORM" == "windows") ]]; then
         echo "Convert ${DOTNETSDK_INSTALLDIR} to Windows style path"
         sdkinstallwindow_path=${DOTNETSDK_INSTALLDIR:1}
         sdkinstallwindow_path=${sdkinstallwindow_path:0:1}:${sdkinstallwindow_path:1}
-        powershell -NoLogo -Sta -NoProfile -NonInteractive -ExecutionPolicy Unrestricted -Command "& \"./Misc/dotnet-install.ps1\" -Version ${DOTNETSDK_VERSION} -InstallDir \"${sdkinstallwindow_path}\" -NoPath; exit $LastExitCode;" || checkRC dotnet-install.ps1
+        powershell -NoLogo -Sta -NoProfile -NonInteractive -ExecutionPolicy Unrestricted -Command "& \"./Misc/dotnet-install.ps1\" -Version ${DOTNETSDK_VERSION} -InstallDir \"${sdkinstallwindow_path}\" -NoPath; exit \$LastExitCode;" || checkRC dotnet-install.ps1
     else
-        bash ./Misc/dotnet-install.sh --version ${DOTNETSDK_VERSION} --install-dir ${DOTNETSDK_INSTALLDIR} --no-path || checkRC dotnet-install.sh
+        bash ./Misc/dotnet-install.sh --version ${DOTNETSDK_VERSION} --install-dir "${DOTNETSDK_INSTALLDIR}" --no-path || checkRC dotnet-install.sh
     fi
 
-    echo "${DOTNETSDK_VERSION}" > ${DOTNETSDK_INSTALLDIR}/.${DOTNETSDK_VERSION}
+    echo "${DOTNETSDK_VERSION}" > "${DOTNETSDK_INSTALLDIR}/.${DOTNETSDK_VERSION}"
 fi
 
 echo "Prepend ${DOTNETSDK_INSTALLDIR} to %PATH%"
@@ -231,8 +221,8 @@ heading "Pre-cache external resources for $RUNTIME_ID package ..."
 bash ./Misc/externals.sh $RUNTIME_ID "Pre-Cache" || checkRC "externals.sh Pre-Cache"
 
 if [[ "$CURRENT_PLATFORM" == 'windows' ]]; then
-    vswhere=`find $DOWNLOAD_DIR -name vswhere.exe | head -1`
-    vs_location=`$vswhere -latest -property installationPath`
+    vswhere=$(find "$DOWNLOAD_DIR" -name vswhere.exe | head -1)
+    vs_location=$("$vswhere" -latest -property installationPath)
     msbuild_location="$vs_location""\MSBuild\15.0\Bin\msbuild.exe"
 
     if [[ ! -e "${msbuild_location}" ]]; then