diff --git a/extra/udfhack/linux/README.txt b/extra/udfhack/linux/README.txt
new file mode 100644
index 000000000..a15b58895
--- /dev/null
+++ b/extra/udfhack/linux/README.txt
@@ -0,0 +1,22 @@
+Before compiling, you need to adapt the following to your environment:
+
+Variables in install.sh script:
+--------------------------------------------------------------------------
+Variable name			Variable description
+--------------------------------------------------------------------------
+USER                    Database management system administrative username
+PORT                    Database management system port
+VERSION                 Database management system version (PostgreSQL only)
+
+Variable in Makefile (MySQL only):
+--------------------------------------------------------------------------
+Variable name			Variable description
+--------------------------------------------------------------------------
+LIBDIR                  Database management system absolute file system
+                        path for third party libraries
+
+Then you can launch './install.sh' if you want to compile the shared
+object from the source code and create the user-defined functions on the
+database management system.
+If you only want to compile the shared object, you need to call only the
+'make' command.
diff --git a/extra/udfhack/linux/lib_mysqludf_sys/install.sh b/extra/udfhack/linux/lib_mysqludf_sys/install.sh
index ff1080da9..8618c9a63 100755
--- a/extra/udfhack/linux/lib_mysqludf_sys/install.sh
+++ b/extra/udfhack/linux/lib_mysqludf_sys/install.sh
@@ -20,8 +20,8 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 
 # Adapt the following settings to your environment
-PORT="3306"
 USER="root"
+PORT="3306"
 
 echo "Compiling the MySQL UDF"
 make