Lately in Ubuntu 10.04 I got upon login two times the output about the number of packages available to be updated. One of them always outdated. I have long tried to find the reason and finally managed to.
The problem was that apparently at some point a file named /etc/motd.tail was in use and was more or less retired (at least for the purpose of showing the information about available packages). In its stead the file /etc/motd is used. All I did to get rid of the nuisance was to execute:
echo -ne ''|sudo tee /etc/motd.tail
That got rid of the bugger. Besides, this trick with sudo and tee can be used to use pipes instead of shell redirectors to write to files only accessible to root. Note that you can use tee -a if you merely wish to append to an existing file.
// Oliver