Note that install_server.sh is not for Mac OSX

It will fail pretty quickly since there is no -f
readlink flag there.

README.md

@@ -166,6 +166,8 @@ for Ubuntu and Debian systems:
     % cd utils
     % ./install_server.sh
 
+_Note_: `install_server.sh` will not work on Mac OSX; it is built for Linux only.
+
 The script will ask you a few questions and will setup everything you need
 to run Redis properly as a background daemon that will start again on
 system reboots.

utils/install_server.sh

@@ -43,6 +43,9 @@
 #
 # /!\ This script should be run as root
 #
+# NOTE: This script will not work on Mac OSX.
+#       It supports Debian and Ubuntu Linux.
+#
 ################################################################################
 
 die () {