how to implement tail -n

["Venkatesh Joshi" <joshiv@cisco.com>]

Hi,

I would like to know how to implement "tail -n" in C.

The "-n" option will be used to print the last n lines of a file -
rather than the default option of printing the last 10 lines of a file.

I wish to do this in a single pass. I can use lseek() to go to the end
of the file. How to traverse backwards from there ? Is there any
function that does this ?

thanks,
venkatesh