update install.sh

sh/install.sh

@@ -129,8 +129,13 @@ create_ssl_cert(){
 pre_install_spider(){
     echo "当前进度:10.下载爬虫源码"
     cd $PUBLIC_DIR
+    if [ -d "learn-spider" ]; then
+        cd learn-spider
+        sudo git pull
+    else
         sudo git clone $GIT_PY_SPIDER
         cd learn-spider
+    fi
     sudo chmod +x ./pre_install_spider.sh
     sudo chmod +x ./start_spider.sh
     sudo ./pre_install_spider.sh