stat is a system call that returns the "stat" data structure of a file, if possible. cLIeNUX also provides a commandline wrapper, a "bonker", for stat.
The syscall stat
The asm include file
stat.h
The cLIeNUX stat command hardly merits a manpage. Just do
stat / stat /COPYING stat /dev/null stat /dev/fd0to see what it does. If you strace most programs you will see that stat is a very important syscall.