Advise needed to write a script

[Mark Pearce]

Hi

I have a permanent internet connection using modems.  Every now and then
I loose my connection, or at least, I loose the IP but I remain
connected.  If I reboot my box, I come back online with the IP address
and everything works 100%, then a while later the IP dissapears but I
remain connected.

I have found 2 ways to resolve this, either reboot the server or write a
script that kills and restarts ppp, I am using userland-ppp.

What I would like to do is the following.
create a script that runs contineously in the background, checking on
the IP address every 5 minutes, and if it's not there, run a script to
kill and restart ppp.

I have no clue where to start on this.

I'd appreciate any info on writing something or pointing me in the right
direction to resolve this problem.

Thanks

Mark