Calling system processes

[Mike Shepherd]

	I was wondering if there is a way to call system processes from a 
C program, and how it would be done (this like 'ls','cd','more')?  I am
most interest in the ability to change directories though.

	Also, is there a way to call other system programs like 'vi' or
'mail'?  Is it used different than simple system calls?

Thanks,
Mike
-- 
*   Mike Shepherd	(shepherd at mentor.cc.purdue.edu)			      *
*******************************************************************************
* Sometimes I think the surest sign that intelligent life exists elsewhere in *
* the universe is that none of it has tried to contact us.    --Calvin of C&H *