Paul A Vixie wrote:

> > So my question is this: what is the simplest, most elegant way to have a
> > system task run when the load average gets too high? Also, is there an
> > easy way, if any, to have cron not run a job if the last instance of that
> > job is still running? Or would a little external logic be in order?
> 
> cron does not have that feature, but something like the old c-news shell
> wrapper that got a lock, ran a program of some kind, and destroyed the lock
> seems to be in order.  (for extra credit, give it a command line option to
> either wait, or just die, if the lock isn't gettable.)

The lockfile program that comes with procmail is useful in shell scripts
for manipulating lockfiles.

Simon.
--
Simon Burge                            <simonb@wasabisystems.com>
NetBSD CDs, Support and Service:    http://www.wasabisystems.com/