The autorun.txt file runs when the client is first started. Here are some examples of what can be used in the autorun.txt file which have been taken from multiple sources of the Wurmpedia.
The following opens windows when the client loads:
toggle skills toggle inventory toggle stats
This prevents the target bar and the select bar from opening by default at login.
toggle select toggle target
This stops kingdom chat from loading when the game starts, but sometimes someone gets in a message before it takes effect. Placing it at the top of the file may help.
You could add this to know how much sleep bonus you have when you log in. This works best at the bottom of the file.
You could add this to know how long the server has been up. This works best at the bottom of the file.