sudo log file

i have read in a book that the sudo utility logs all commands it executes. this log can be useful for retracing your steps if you make a mistake and for system auditing- what is the name of this log file and where it is located ?

NB:- i use ubuntu 8.04


jerome

/var/log/auth.log

and the older copies will be

/var/log/auth.log.0

/var/log/auth.log.1.gz
/var/log/auth.log.2.gz

etc...