Update 'update.sh'

update.sh

@@ -12,6 +12,14 @@ if [ "$EUID" -ne 0 ]; then
   exit
 fi
 
+# ensure the lsb_release is installed
+# Debian and Ubuntu have it preinstaled already, CentOS needs to have it installed
+type lsb_release >/dev/null 2>&1 || yum install -y redhat-lsb
+
+# get OS ditro and version
+OS=$(lsb_release -si)
+OS_VER=$(lsb_release -sr)
+
 # Debian OS
 if [ -f /etc/debian_version ]; then
     # upgrade all packages