manipulating/testing file times.

[David Collier]

> coreutils' touch actually allows relative dates and times:
> 
>   touch -d "+3 days" FILE
> 
> does what you would expect. That's a potential enhancement to 
> Busybox.

That's very sexy, and pretty close to perfect.

What I'm trying to do is to do a dhcp request - if it fails I want to do
another one, but only every 15 minutes or so. I'm not aware of a built-in
capability of udhcpc to do that, so I need to SIGUSR1 it from time to
time.

I can have a dedicated process which deals with this, but it is actually
easier to debug if I have a file on the machine which has he "time" of
the next moment when I will retry. Then my script just tests "now"
against the file time.

I want to do the same in a shepherd script for dhcp, OpenVPN and a couple
of other things which must run for 5 years! If the processes collapse,
I'll try restarting them, but I'm not going to thrash it every 2 seconds.

Thanks for the help

David