# This is documentation for the getusnoeop k-shell script, which is provided
# as a convenience for users of our USNO EOP data products.  It is to be used
# as an aid and no guarantee is made of its infallibility.  User accepts 
# that the code may require modification in order to meet needs and function
# as intended.  The code was tested on a Linux OS 64-bit system.  All commands
# are standard Linux k-shell commands.

INTENT
The intent of this script is to download new data from our ftp server maia as the primary site and our ftp server toshi in Flagstaff, Arizona as back-up.  The script attempts to download the data from the primary site for approximately 30 minutes.  If no new data is available, the script will attempt to retrieve new data alternatively from both the primary site and secondary site.  The default amount of checking for new data is 2.5 hours.

USAGE
The user should have a previously downloaded local copy of any and all USNO EOP data files with which to compare against the files he/she is attempting to download from our servers.  The script is designed to examine the file time stamp of the local file(s) and the server file(s).  If the server file time stamp is newer, the data will be downloaded.  Otherwise, the script will continue to check for updates until a threshold is reached.  If new data is downloaded, the user will receive an e-mail message alerting he/she that there is new data that was retrieved.  The message will indicate the day and hour of retrieval. 

The user may wish to run the script as a cronjob starting at 17:10 UTC, when the daily EOP generation process is normally completed at USNO.  (Similarly, the user may wish to run the script interactively at near 17:10 UTC).