diff --git a/demos/cluster_serving/install-dependencies.sh b/demos/cluster_serving/install-dependencies.sh
index 0dacfe62..7a5effbc 100755
--- a/demos/cluster_serving/install-dependencies.sh
+++ b/demos/cluster_serving/install-dependencies.sh
@@ -1,13 +1,18 @@
 #!/bin/bash
+set -e
 
-apt-get update
-apt-get install -y openjdk-11-jre
-apt-get install -y netcat
-
-#The openjdk has a broken symlink, remove it as a workaround
-rm /usr/lib/jvm/java-11-openjdk-amd64/lib/security/blacklisted.certs
+OS=`awk -F= '/^NAME/{print $2}' /etc/os-release`
+if [ "$OS" == "\"Ubuntu\"" ]; then
+  apt-get update -y && apt-get install -y openjdk-11-jre netcat
+  # The openjdk has a broken symlink, remove it as a workaround
+  rm -f /usr/lib/jvm/java-11-openjdk-amd64/lib/security/blacklisted.certs
+else
+  echo "Unsupported OS: $OS"
+  exit 1
+fi
 
 # Redis
+rm -rf redis-${REDIS_VERSION}*
 wget http://download.redis.io/releases/redis-${REDIS_VERSION}.tar.gz && \
 tar -zxvf redis-${REDIS_VERSION}.tar.gz
 rm redis-${REDIS_VERSION}.tar.gz
@@ -16,16 +21,18 @@ make
 cd ../
 
 # Flink
+rm -rf flink-${FLINK_VERSION}*
 wget https://archive.apache.org/dist/flink/flink-${FLINK_VERSION}/flink-${FLINK_VERSION}-bin-scala_2.11.tgz
 tar -zxvf flink-${FLINK_VERSION}-bin-scala_2.11.tgz
 rm flink-${FLINK_VERSION}-bin-scala_2.11.tgz
 
 # Analytics Zoo
+rm -rf analytics-zoo-bigdl_*
 wget https://repo1.maven.org/maven2/com/intel/analytics/zoo/analytics-zoo-bigdl_$BIGDL_VERSION-spark_$SPARK_VERSION/$ANALYTICS_ZOO_VERSION/analytics-zoo-bigdl_$BIGDL_VERSION-spark_$SPARK_VERSION-$ANALYTICS_ZOO_VERSION-serving.jar
 wget https://repo1.maven.org/maven2/com/intel/analytics/zoo/analytics-zoo-bigdl_$BIGDL_VERSION-spark_$SPARK_VERSION/$ANALYTICS_ZOO_VERSION/analytics-zoo-bigdl_$BIGDL_VERSION-spark_$SPARK_VERSION-$ANALYTICS_ZOO_VERSION-http.jar
 
 # models
-mkdir resnet50 && \
+rm -rf resnet50 && mkdir resnet50 && \
 cd resnet50 && \
 wget -c "https://sourceforge.net/projects/analytics-zoo/files/analytics-zoo-models/openvino/2018_R5/resnet_v1_50.bin/download" -O resnet_v1_50.bin && \
 wget -c "https://sourceforge.net/projects/analytics-zoo/files/analytics-zoo-models/openvino/2018_R5/resnet_v1_50.xml/download" -O resnet_v1_50.xml
diff --git a/demos/flink/download_flink.sh b/demos/flink/download_flink.sh
index 7a9c9a57..1b7f50ab 100755
--- a/demos/flink/download_flink.sh
+++ b/demos/flink/download_flink.sh
@@ -1,7 +1,18 @@
-apt-get update
-apt-get install -y openjdk-11-jre
-#The openjdk has a broken symlink, remove it as a workaround
-rm /usr/lib/jvm/java-11-openjdk-amd64/lib/security/blacklisted.certs
+#!/bin/bash
+set -e
 
+OS=`awk -F= '/^NAME/{print $2}' /etc/os-release`
+if [ "$OS" == "\"Ubuntu\"" ]; then
+  apt-get update -y && apt-get install -y openjdk-11-jre
+  # The openjdk has a broken symlink, remove it as a workaround
+  rm -f /usr/lib/jvm/java-11-openjdk-amd64/lib/security/blacklisted.certs
+else
+  echo "Unsupported OS: $OS"
+  exit 1
+fi
+
+rm -rf flink-1.10.1*
 wget https://archive.apache.org/dist/flink/flink-1.10.1/flink-1.10.1-bin-scala_2.11.tgz
 tar -xvzf flink-1.10.1-bin-scala_2.11.tgz
+
+echo "Download Flink Success"
diff --git a/demos/grpc/grpc_glibc/download_and_install_grpc_glibc.sh b/demos/grpc/grpc_glibc/download_and_install_grpc_glibc.sh
index b240dbdc..aa9b26f4 100755
--- a/demos/grpc/grpc_glibc/download_and_install_grpc_glibc.sh
+++ b/demos/grpc/grpc_glibc/download_and_install_grpc_glibc.sh
@@ -3,7 +3,7 @@ set -e
 
 GRPC_SRC_DIR=$PWD/grpc_src
 
-mkdir -p $GRPC_SRC_DIR && cd $GRPC_SRC_DIR
+rm -rf $GRPC_SRC_DIR && mkdir -p $GRPC_SRC_DIR && cd $GRPC_SRC_DIR
 git clone https://github.com/grpc/grpc.git .
 git checkout tags/v1.24.3
 
diff --git a/demos/grpc/grpc_glibc/prepare_client_server_glibc.sh b/demos/grpc/grpc_glibc/prepare_client_server_glibc.sh
index 7404db7a..9fab3b35 100755
--- a/demos/grpc/grpc_glibc/prepare_client_server_glibc.sh
+++ b/demos/grpc/grpc_glibc/prepare_client_server_glibc.sh
@@ -4,7 +4,7 @@ set -e
 export LD_LIBRARY_PATH="/usr/local/lib:$LD_LIBRARY_PATH"
 
 cd grpc_src/examples/cpp/helloworld
-mkdir -p cmake/build && cd cmake/build
+rm -rf cmake/build && mkdir -p cmake/build && cd cmake/build
 cmake ../.. \
 	-DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_FLAGS="-fPIC -pie" -DCMAKE_C_FLAGS="-fPIC -pie"
 make -j$(nproc)
diff --git a/demos/grpc/grpc_glibc/prepare_stress_test_tool.sh b/demos/grpc/grpc_glibc/prepare_stress_test_tool.sh
index b8c4f8bf..f60795c2 100755
--- a/demos/grpc/grpc_glibc/prepare_stress_test_tool.sh
+++ b/demos/grpc/grpc_glibc/prepare_stress_test_tool.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-mkdir ghz_src && cd ghz_src
+rm -rf ghz_src && mkdir ghz_src && cd ghz_src
 git clone https://github.com/bojand/ghz .
 git checkout tags/v0.105.0
 make build
diff --git a/demos/grpc/grpc_musl/download_and_install_grpc.sh b/demos/grpc/grpc_musl/download_and_install_grpc.sh
index 4c2110e9..970f6f91 100755
--- a/demos/grpc/grpc_musl/download_and_install_grpc.sh
+++ b/demos/grpc/grpc_musl/download_and_install_grpc.sh
@@ -5,6 +5,7 @@ export PATH=$PATH:$INSTALL_DIR/bin
 # Tell CMake to search for packages in Occlum toolchain's directory only
 export PKG_CONFIG_LIBDIR=$INSTALL_DIR/lib
 
+rm -rf grpc
 git clone https://github.com/grpc/grpc.git 
 cd grpc
 git checkout tags/v1.24.3
diff --git a/demos/grpc/grpc_musl/download_and_install_openssl.sh b/demos/grpc/grpc_musl/download_and_install_openssl.sh
index b139c0b8..c46620c5 100755
--- a/demos/grpc/grpc_musl/download_and_install_openssl.sh
+++ b/demos/grpc/grpc_musl/download_and_install_openssl.sh
@@ -1,6 +1,7 @@
 #!/bin/sh
 #copyright@antfinancial:adopted from a script written by geding
 
+rm -rf openssl
 git clone http://github.com/openssl/openssl
 cd openssl
 git checkout tags/OpenSSL_1_1_1
diff --git a/demos/grpc/grpc_tls/download_and_install_grpc.sh b/demos/grpc/grpc_tls/download_and_install_grpc.sh
index 0e05aa43..8f1e5286 100755
--- a/demos/grpc/grpc_tls/download_and_install_grpc.sh
+++ b/demos/grpc/grpc_tls/download_and_install_grpc.sh
@@ -13,11 +13,13 @@ export PATH=$PATH:$INSTALL_DIR/bin
 export PKG_CONFIG_LIBDIR=$INSTALL_DIR/lib
 
 # Download grpc
+rm -rf v${GRPC_VER}*
 wget https://github.com/grpc/grpc/archive/refs/tags/v${GRPC_VER}.tar.gz
 rm -rf ${GRPC_SRC_DIR} && mkdir ${GRPC_SRC_DIR}
 tar zxvf v${GRPC_VER}.tar.gz -C ${GRPC_SRC_DIR} --strip-components 1
 
 # Download and Install c-ares
+rm -rf cares-${CARES_VER}*
 wget https://github.com/c-ares/c-ares/archive/refs/tags/cares-${CARES_VER}.tar.gz
 tar zxvf cares-${CARES_VER}.tar.gz -C ${GRPC_SRC_DIR}/third_party/cares/cares/ --strip-components 1
 cd $GRPC_SRC_DIR/third_party/cares/cares
@@ -33,6 +35,7 @@ make install
 cd $PWD
 
 # Download and Install protobuf
+rm -rf v${RPOTOBUF_VER}*
 wget https://github.com/protocolbuffers/protobuf/archive/refs/tags/v${RPOTOBUF_VER}.tar.gz
 tar zxvf v${RPOTOBUF_VER}.tar.gz -C $GRPC_SRC_DIR/third_party/protobuf/ --strip-components 1
 cd $GRPC_SRC_DIR/third_party/protobuf
@@ -50,7 +53,7 @@ cmake ../ \
 make -j$(nproc)
 make install
 
-cp $INSTALL_DIR/bin/protoc /usr/bin
+cp -f $INSTALL_DIR/bin/protoc /usr/bin
 
 # Install gRPC
 cd $GRPC_SRC_DIR/cmake
diff --git a/demos/grpc/grpc_tls/download_and_install_openssl.sh b/demos/grpc/grpc_tls/download_and_install_openssl.sh
index 3bfdda5f..5a35bb92 100755
--- a/demos/grpc/grpc_tls/download_and_install_openssl.sh
+++ b/demos/grpc/grpc_tls/download_and_install_openssl.sh
@@ -2,6 +2,7 @@
 #copyright@antfinancial:adopted from a script written by geding
 set -e
 
+rm -rf openssl
 git clone -b OpenSSL_1_1_1 --depth 1 http://github.com/openssl/openssl
 cd openssl
 CC=occlum-gcc ./config \
diff --git a/demos/https_server/download_and_build_mongoose.sh b/demos/https_server/download_and_build_mongoose.sh
index aa27e3f4..488dd211 100755
--- a/demos/https_server/download_and_build_mongoose.sh
+++ b/demos/https_server/download_and_build_mongoose.sh
@@ -2,7 +2,7 @@
 set -e
 
 # 1. Download and install OpenSSL 1.1.1
-mkdir -p deps/openssl
+rm -rf deps/openssl && mkdir -p deps/openssl
 pushd deps/openssl
 git clone https://github.com/openssl/openssl .
 git checkout tags/OpenSSL_1_1_1 -b OpenSSL_1_1_1
@@ -16,7 +16,7 @@ sudo make install
 popd
 
 # 2. Download Mongoose 6.15
-mkdir -p mongoose_src
+rm -rf mongoose_src && mkdir -p mongoose_src
 pushd mongoose_src
 git clone https://github.com/cesanta/mongoose .
 git checkout tags/6.15 -b 6.15
@@ -26,3 +26,5 @@ popd
 pushd mongoose_src/examples/simplest_web_server_ssl
 CC=occlum-gcc CFLAGS_EXTRA="-Wno-format-truncation" make
 popd
+
+echo "Build Mongoose Success"
diff --git a/demos/openvino/install_cmake.sh b/demos/openvino/install_cmake.sh
index cc99829c..c6c223b8 100755
--- a/demos/openvino/install_cmake.sh
+++ b/demos/openvino/install_cmake.sh
@@ -1,8 +1,14 @@
 #!/bin/bash
 set -e
-cd ~
+
+# Skip install if current cmake is newer
+CURRENT_VER=`cmake --version | head -n1 | sed 's/[^0-9.]*//g'`
+MIN_VER=3.15.5
+echo -e "$MIN_VER\n$CURRENT_VER" \ | sort -V | head -n1 | grep -q $MIN_VER && exit 0
+
+rm -rf cmake-3.15.5*
 wget https://github.com/Kitware/CMake/releases/download/v3.15.5/cmake-3.15.5.tar.gz && tar xf cmake-3.15.5.tar.gz
 cd cmake-3.15.5
 ./bootstrap
-make -j4
+make -j$(nproc)
 sudo make install
diff --git a/demos/tensorflow/tensorflow_serving/build_occlum_tf_serving.sh b/demos/tensorflow/tensorflow_serving/build_occlum_tf_serving.sh
index df47c5ec..61a9b211 100755
--- a/demos/tensorflow/tensorflow_serving/build_occlum_tf_serving.sh
+++ b/demos/tensorflow/tensorflow_serving/build_occlum_tf_serving.sh
@@ -1,4 +1,6 @@
-#!/bin/sh
+#!/bin/bash
+set -e
+
 echo Building tf-serving with pic
 cd docker
 ./build_tf_serving_with_pic.sh
diff --git a/demos/tensorflow/tensorflow_serving/client/prepare_client_env.sh b/demos/tensorflow/tensorflow_serving/client/prepare_client_env.sh
index eb7e0888..2e1a4753 100755
--- a/demos/tensorflow/tensorflow_serving/client/prepare_client_env.sh
+++ b/demos/tensorflow/tensorflow_serving/client/prepare_client_env.sh
@@ -1,3 +1,11 @@
-apt update
-apt install -y libgl1-mesa-glx
+#!/bin/bash
+set -e
+
+OS=`awk -F= '/^NAME/{print $2}' /etc/os-release`
+if [ "$OS" == "\"Ubuntu\"" ]; then
+  apt-get update -y && apt-get install -y libgl1-mesa-glx
+else
+  yum install -y mesa-libGL
+fi
+
 pip3 install -r requirements.txt -v
diff --git a/demos/tensorflow/tensorflow_serving/download_model.sh b/demos/tensorflow/tensorflow_serving/download_model.sh
index 789004af..06b132ad 100755
--- a/demos/tensorflow/tensorflow_serving/download_model.sh
+++ b/demos/tensorflow/tensorflow_serving/download_model.sh
@@ -1,8 +1,11 @@
+#!/bin/bash
+set -e
+
 cur_dir=`pwd -P`
 models_abs_dir=${cur_dir}/models
-mkdir ${models_abs_dir}
+rm -rf ${models_abs_dir} && mkdir ${models_abs_dir}
 
 # resnet50-v15
-mkdir ${models_abs_dir}/resnet50-v15-fp32
+rm -rf ${models_abs_dir}/resnet50-v15-fp32 && mkdir ${models_abs_dir}/resnet50-v15-fp32
 cd ${models_abs_dir}/resnet50-v15-fp32
 wget --no-check-certificate -c https://storage.googleapis.com/intel-optimized-tensorflow/models/v1_8/resnet50_fp32_pretrained_model.pb -O resnet50-v15-fp32.pb
diff --git a/demos/tensorflow/tensorflow_serving/generate_ssl_config.sh b/demos/tensorflow/tensorflow_serving/generate_ssl_config.sh
index 53fbafa5..be958189 100755
--- a/demos/tensorflow/tensorflow_serving/generate_ssl_config.sh
+++ b/demos/tensorflow/tensorflow_serving/generate_ssl_config.sh
@@ -1,3 +1,6 @@
+#!/bin/bash
+set -e
+
 service_domain_name=$1
 
 rm -rf ssl_configure
diff --git a/demos/tensorflow/tensorflow_serving/prepare_model_and_env.sh b/demos/tensorflow/tensorflow_serving/prepare_model_and_env.sh
index a1a9e458..d11ab14b 100755
--- a/demos/tensorflow/tensorflow_serving/prepare_model_and_env.sh
+++ b/demos/tensorflow/tensorflow_serving/prepare_model_and_env.sh
@@ -1,5 +1,13 @@
-apt-get update
-apt install -y python3-pip 
+#!/bin/bash
+set -e
+
+OS=`awk -F= '/^NAME/{print $2}' /etc/os-release`
+if [ "$OS" == "\"Ubuntu\"" ]; then
+  apt-get update -y && apt-get install -y python3-pip
+else
+  yum install -y python3-pip
+fi
+
 pip3 install --upgrade pip
 pip3 install --upgrade tensorflow==2.4
 ./download_model.sh
diff --git a/demos/tensorflow_lite/download_and_build_tflite.sh b/demos/tensorflow_lite/download_and_build_tflite.sh
index 14bfcda9..98ebf9a1 100755
--- a/demos/tensorflow_lite/download_and_build_tflite.sh
+++ b/demos/tensorflow_lite/download_and_build_tflite.sh
@@ -3,7 +3,7 @@ set -e
 SRC_DIR="tensorflow_src"
 
 # 1. Build tensorflow lite and the demo program
-mkdir -p $SRC_DIR
+rm -rf $SRC_DIR && mkdir -p $SRC_DIR
 pushd $SRC_DIR
 git clone https://github.com/tensorflow/tensorflow .
 git checkout tags/v1.15.0-rc0 -b v1.15.0-rc0
@@ -15,7 +15,7 @@ make -j 3 -f tensorflow/lite/tools/make/Makefile
 popd
 
 # 2. Download tflite model and labels
-mkdir models
+rm -rf models && mkdir models
 curl https://storage.googleapis.com/download.tensorflow.org/models/mobilenet_v1_2018_02_22/mobilenet_v1_1.0_224.tgz | tar xzv -C ./models
 curl https://storage.googleapis.com/download.tensorflow.org/models/mobilenet_v1_1.0_224_frozen.tgz  | tar xzv -C ./models  mobilenet_v1_1.0_224/labels.txt
 mv ./models/mobilenet_v1_1.0_224/labels.txt ./models/labels.txt
diff --git a/demos/xgboost/download_and_build_xgboost.sh b/demos/xgboost/download_and_build_xgboost.sh
index c8975181..ab6d8786 100755
--- a/demos/xgboost/download_and_build_xgboost.sh
+++ b/demos/xgboost/download_and_build_xgboost.sh
@@ -5,8 +5,12 @@ set -e
 export PKG_CONFIG_LIBDIR=/usr/local/occlum/x86_64-linux-musl/lib
 
 # Install the dependencies
-apt-get update
-apt-get install -y python3-pip python3-setuptools
+OS=`awk -F= '/^NAME/{print $2}' /etc/os-release`
+if [ "$OS" == "\"Ubuntu\"" ]; then
+  apt-get update -y && apt-get install -y python3-pip python3-setuptools
+else
+  yum install -y python3-pip python3-setuptools
+fi
 pip3 install kubernetes
 
 #install the cmake
diff --git a/demos/xgboost/install_cmake.sh b/demos/xgboost/install_cmake.sh
index 87992079..c6c223b8 100755
--- a/demos/xgboost/install_cmake.sh
+++ b/demos/xgboost/install_cmake.sh
@@ -1,6 +1,12 @@
 #!/bin/bash
 set -e
-cd ~
+
+# Skip install if current cmake is newer
+CURRENT_VER=`cmake --version | head -n1 | sed 's/[^0-9.]*//g'`
+MIN_VER=3.15.5
+echo -e "$MIN_VER\n$CURRENT_VER" \ | sort -V | head -n1 | grep -q $MIN_VER && exit 0
+
+rm -rf cmake-3.15.5*
 wget https://github.com/Kitware/CMake/releases/download/v3.15.5/cmake-3.15.5.tar.gz && tar xf cmake-3.15.5.tar.gz
 cd cmake-3.15.5
 ./bootstrap