Sometimes you have found mail command is missing on your UNIX system. It is in ‘mailutils’ package of GNU. So you have to download from http://mailutils.org/ and need compiling it. Or maybe you can find rpm. If you are CentOS user, you can find mailx with yum command.
By the way, I found something pretty cool. This is called ‘Linux Beauty’. It shows us linux commands with beautiful girl from Kobe city. Enjoy!