Update MOTD

When logging into an Ubuntu server you may have noticed the informative Message Of The Day (MOTD). This information is obtained and displayed using a couple of packages:

landscape-common: provides the core libraries of landscape-client, which can be used to manage systems using the web based Landscape application. The package includes the /usr/bin/landscape-sysinfo utility which is used to gather the information displayed in the MOTD.
update-motd: is used to automatically update the MOTD via cron.

The update-motd utility has several options to further customize the MOTD:

--disable: prevents automatic updates of the MOTD. Using this option creates the /var/lib/update-motd/disabled file, which if present stops update-motd from modifying /etc/motd.
--enable: enables the automatic MOTD updates. If /var/lib/update-motd is present it will be removed.
--force: does a one time update of /etc/motd, overriding update-motd if it has been disabled.
d, hourly, weekly, monthly: option will run the scripts in /etc/update-motd.d/ (default), /etc/update-motd.d/hourly, /etc/update-motd.d/weekly, or /etc/update-motd.d/monthly respectively.

update-motd executes the scripts in /etc/update-motd.d in order based on the number prepended to the script. Separate cron scripts execute every ten minutes, hourly, weekly, and monthly running the corresponding scripts in /etc/update-motd.d. The output of the scripts is written to /var/run/update-motd/, keeping the numerical order, then concatenated with /etc/motd.tail and written to /etc/motd.

You can add your own dynamic information to the MOTD. For example, to add local weather information:

First, install the weather-util package:
```
sudo apt-get install weather-util
```
The weather utility uses METAR data from the National Oceanic and Atmospheric Administration and forecasts from the National Weather Service. In order to find local information you will need the 4-character ICAO location indicator. This can be determined by browsing to the National Weather Service site.

Although the National Weather Service is a United States government agency there are weather stations available world wide. However, local weather information for all locations outside the U.S. may not be available.

Create /usr/local/bin/local-weather, a simple shell script to use weather with your local ICAO indicator:

#!/bin/sh
##########################################################################
#
# Prints the local weather to /var/run/update-motd/60-local-weather  
# for update-motd.
#
##########################################################################

# Replace KINT with your local weather station.
# Local stations can be found here: http://www.weather.gov/tg/siteloc.shtml

echo "" > /var/run/update-motd/60-local-weather
weather -i KINT >> /var/run/update-motd/60-local-weather

Make the script executable:

sudo chmod 755 /usr/local/bin/local-weather

Next, create a symlink to /etc/update-motd.d/60-local-weather:

sudo ln -s /usr/local/bin/local-weather /etc/update-motd.d/60-local-weather

Finally, update the MOTD:
```
sudo update-motd
```

You should now be greeted with some useful information, and some information about the local weather that may not be quite so useful. Hopefully the local-weather example demonstrates the flexibility of update-motd.


19. fejezet - Other Useful Applications		etckeeper