diff --git a/Unreal/Environments/Blocks/clean.sh b/Unreal/Environments/Blocks/clean.sh
old mode 100644
new mode 100755
diff --git a/Unreal/Environments/Blocks/update_from_git.sh b/Unreal/Environments/Blocks/update_from_git.sh
old mode 100644
new mode 100755
index 1460568547..2f57806129
--- a/Unreal/Environments/Blocks/update_from_git.sh
+++ b/Unreal/Environments/Blocks/update_from_git.sh
@@ -1,6 +1,13 @@
-scr_dir=`realpath $0`
-rsync -a --delete ../../Plugins/AirSim Plugins/AirSim
-robocopy /MIR ..\..\Plugins\AirSim Plugins\AirSim /XD temp *. /njh /njs /ndl /np
-robocopy /MIR ..\..\..\AirLib Plugins\AirSim\Source\AirLib /XD temp *. /njh /njs /ndl /np
+#! /bin/bash
 
-pause
\ No newline at end of file
+# get path of current script: https://stackoverflow.com/a/39340259/207661
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+pushd "$SCRIPT_DIR"
+
+set -e
+set +x
+
+rsync -a  --exclude 'temp' --delete ../../Plugins/AirSim Plugins/AirSim
+rsync -a  --exclude 'temp' --delete ../../../AirLib Plugins/AirSim/Source/AirLib
+
+popd
\ No newline at end of file
diff --git a/clean.sh b/clean.sh
old mode 100644
new mode 100755
diff --git a/cmake/cmake-modules/CommonSetup.cmake b/cmake/cmake-modules/CommonSetup.cmake
index 2592e312ea..fe424d9060 100644
--- a/cmake/cmake-modules/CommonSetup.cmake
+++ b/cmake/cmake-modules/CommonSetup.cmake
@@ -23,6 +23,7 @@ macro(CommonSetup)
             set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__CLANG__")
         else ()
             ##TODO: Werror removed temporarily. It should be added back after Linux build is stable
+            # other flags used in Unreal: -funwind-tables  -fdiagnostics-format=msvc -fno-inline  -fno-omit-frame-pointer  -fstack-protector -O2
             set(CMAKE_CXX_FLAGS "-std=c++14 -ggdb  -Wall -Wextra -Wstrict-aliasing -Wunreachable-code -Wcast-qual -Wctor-dtor-privacy -Wdisabled-optimization -Wformat=2 -Winit-self -Wmissing-include-dirs -Wold-style-cast -Woverloaded-virtual -Wredundant-decls -Wshadow -Wstrict-overflow=5 -Wswitch-default -Wundef -Wno-unused -Wno-variadic-macros -Wno-parentheses -fdiagnostics-show-option ${MAVLINK_OVERRIDES} ${AIRLIB_OVERRIDES} ${RPC_LIB_DEFINES} ${CMAKE_CXX_FLAGS}")
 
             if (${CMAKE_CXX_COMPILER_ID} MATCHES "Clang")
diff --git a/cmake/getlibcxx.sh b/cmake/getlibcxx.sh
index a2690fd8e2..26bb1317dc 100755
--- a/cmake/getlibcxx.sh
+++ b/cmake/getlibcxx.sh
@@ -1,25 +1,33 @@
-#! /bin/bash
+#! /bin/bash
+
+set +x
+set -e
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-cd "$SCRIPT_DIR"
+pushd "$SCRIPT_DIR"
 
 # add llvm-source to root of AirSim
 cd ..
 
 # Checkout LLVM sources
-git clone --depth=1 https://github.com/llvm-mirror/llvm.git llvm-source
-git clone --depth=1 https://github.com/llvm-mirror/libcxx.git llvm-source/projects/libcxx
-git clone --depth=1 https://github.com/llvm-mirror/libcxxabi.git llvm-source/projects/libcxxabi
+# git clone --depth=1 -b release_39  https://github.com/llvm-mirror/llvm.git llvm-source
+# git clone --depth=1 -b release_39  https://github.com/llvm-mirror/libcxx.git llvm-source/projects/libcxx
+# git clone --depth=1 -b release_39  https://github.com/llvm-mirror/libcxxabi.git llvm-source/projects/libcxxabi
+
+# Build and install libc++ 
+rm -rf llvm-build
+mkdir llvm-build && cd llvm-build
 
 export C_COMPILER=clang
 export COMPILER=clang++
 
 # Build and install libc++ 
-mkdir llvm-build && cd llvm-build
 cmake -DCMAKE_C_COMPILER=${C_COMPILER} -DCMAKE_CXX_COMPILER=${COMPILER} \
+      -DLIBCXX_INSTALL_EXPERIMENTAL_LIBRARY=ON  \
       -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_INSTALL_PREFIX=/usr \
-      ../llvm-source
-make cxx
-sudo make install-cxxabi install-cxx
+            ../llvm-source
+            make cxx
+
+sudo make install-libcxx install-libcxxabi 
 
 popd
\ No newline at end of file
diff --git a/cmake/getlibcxx_clean.sh b/cmake/getlibcxx_clean.sh
new file mode 100755
index 0000000000..436c709392
--- /dev/null
+++ b/cmake/getlibcxx_clean.sh
@@ -0,0 +1,12 @@
+#! /bin/bash
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+pushd "$SCRIPT_DIR"
+
+# add llvm-source to root of AirSim
+cd ..
+
+rm -rf  llvm-source
+rm -rf  llvm-build
+
+popd
\ No newline at end of file