Send email on calls to su

["Sam Kuper" <sam.kuper@uclmail.net>]

Dear list,

I want my server to send me an email every time the su command is run. Ideally, I would also like the email to tell me whether the command was run successfully or not. I do not want to modify su itself, and it is important to me that whatever changes I make will survive apt-get upgrade commands without requiring intervention. What is the best way to do this? If there are several good ways you can think of, please could you list them all and, ideally, also give their advantages and disadvantages.

Many thanks indeed,

Sam

PS. I'm still pretty new to system administration, so forgive me if I've missed something obvious.