[plug] checking for existence of an application

[James Devenish]

In message <sf3404ad.069 at mmtnetworks.com.au>
on Fri, Aug 08, 2003 at 08:14:33PM +0800, Jon  Miller wrote:
> I only require the name of the MTA, from there I can issue the commands I need.

In Linux and UNIX circles, this is known as the "path" of the MTA (all
lowercase letters, not to be confused with the "PATH" environment
variable). /usr/bin/mail and /usr/lib/sendmail are fairly standard paths
for sending mail from the command line under Sys V-like operating
systems (regardless of the MTA).

> Basically, I only need to start and stop the mail server.

Okay, but that is a *very special requirement* and needed to be stated
explicitly. The path and procedure for this will vary amongst operating
systems and even amongst distros! Maybe someone else knows how to solve
this problem generically for Linux distros? Maybe the most robust
solution is to find out about the systems on which the script will be
running and view those as the special cases that the script can handle.