Add README file

README

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+Check Update script for Roundcube Webmail
+=========================================
+
+This script permit to check if an Roundcube Webmail is up to date.
+
+It retreive current stable version on Roundcube Webmail Website and
+compare it to the local version. If the local version is different
+than the current stable version, it notify you by email.
+
+The original script it design to be run by cron, but you could now
+use the script as Nagios check plugin (-n parameter).
+
+Upgrading your Roundcube Webmail installation
+---------------------------------------------
+
+The script could also help you to upgrade your installation. By
+running the script with the -u parameter, it will automatically :
+ - download and uncompress for you the newest version from Roundcube
+   Webmail Website in an upstream directory
+ - duplicate current installation data in a new directory
+ - upgrade this duplicated installation by using 'installto.sh' script
+   provide by Roundcube Webmail project
+ - Optional : execute a custom bash function after_upgrade() if defined.
+   It could be useful if you have custom modification in your installation.
+ - If the current installation path is a symlink, it propose you to change
+   the destionation of this symlink to the new installation path.
+
+Usage
+-----
+
+  Usage : ./check_rc_upgrade.sh [-v] [-n] [-d] [-u]
+    -v   Verbose mode
+    -n   Nagios mode
+    -d   Download new release
+    -u   Upgrade installation
+    -j   Just display current stable version
+    -h   Display this help
+
+Configuration
+-------------
+
+The configuration of this script is located on top of it. It recommand
+to copy the variables in a second file check_rc_upgrade.sh.local. This
+file will be included if present.
+
+Parameters :
+
+ - RC_HOME :
+    The full path of your  Roundcube Webmail installation
+
+ - MAIL :
+    The email address that will be notified on upgrade available (POSIX
+    root user by default)
+
+ - SEND_EVERY_NB_DAY : 
+    The frequency of upgrade available notification (in days, 7 by default)
+
+ - CACHE :
+    The path of a cache file use to keep the lastest upgrade notification.
+    (By default : .cache_check_upgrade file in the parent directory of your
+    Roundcube Webmail installation)
+
+ - CACHE_FAILED :
+    The path of a cache file use to keep the number of check failed.
+    (By default : $CACHE suffix with '.failed')
+
+ - MAX_CHECK :
+    The maximum number of attempts to retreive current stable version on
+    Roundcube Webmail Website. (10 by default)
+    
+ - MAX_FAILED :
+    The maximum number of check failed before notify by email (3 by default)
+
+ - SLEEP_ON_FAILED :
+    The number of second to sleep between to attempts  to retreive current 
+    stable version on Roundcube Webmail Website. (10 by default)
+
+ - CHECK_URL :
+    The URL use to retrieve the lastest Roundcube Webmail version.
+    (By default : http://www.roundcube.net/download)
+
+ - DOWNLOAD :
+    If this variable is set to 1, the newest version will be automatically
+    download in the download directory. (Default : 0)
+
+ - DOWNLOAD_DIR :
+    The path of the download directory. (Default : upstream directory in
+    the parent directory of your Roundcube Webmail installation)