Sometimes, when I log into a box and 'su' to root, I get a cute little message saying I have mail (thank GOD it's not AOL). - Where is this mail? - What does it contain? - Who/What sent it? - How important is it? Is this even actual "mail" in the same sense as email? Or is it just my system telling me something? **EDIT:** In relation to [this][1] question, would I be able to send myself mail using the sendmail program like so: `email@localhost`? [1]: https://superuser.com/questions/306995/why-cant-i-email-myself-at-myemail74-125-235-55