perl or shell script for ip manipulation

Hello,
I'm wanting to develope a script for ip change notification. Since my
box doesn't change cleanly, i'd like to run this script from cron say every
30 minutes. First thing it does is checks the IP, if it's the same as 30
minutes ago it pings one of about ten sites from a list in random order. If
that works, everything is well exit. If not meaning the ip test reports the
same as 30 minutes ago but pinging that list returns nothing then run three
commands, obtain the new ip, save it, and send an email to a designated
address.
I'm not sure if i should do this in shell or perl, as of right now i
have the ip address printing, but i believe i'd have to do something with
saving state between script loads, this i've never done. If anyone has any
suggestions i'd appreciate them.
Thanks.
Dave.

Re: perl or shell script for ip manipulation

In article <476ca4c0$0$32506$4c368faf@roadrunner.com>,
"Dave" wrote:

> Hello,
> I'm wanting to develope a script for ip change notification. Since my
> box doesn't change cleanly, i'd like to run this script from cron say every
> 30 minutes. First thing it does is checks the IP, if it's the same as 30
> minutes ago it pings one of about ten sites from a list in random order. If
> that works, everything is well exit. If not meaning the ip test reports the
> same as 30 minutes ago but pinging that list returns nothing then run three
> commands, obtain the new ip, save it, and send an email to a designated
> address.
> I'm not sure if i should do this in shell or perl, as of right now i
> have the ip address printing, but i believe i'd have to do something with
> saving state between script loads, this i've never done. If anyone has any
> suggestions i'd appreciate them.
> Thanks.
> Dave.

Write the state to a file, and read it back in the next time you run.
If you do it in shell, a simple way to implement this would be to format
the file as a bunch of variable assignments; use ". filename" to execute
the file, and the variables will be assigned those values. In Perl you
could use a hash. Write a sequence of VARIABLE VALUE lines to
the file, and then read it back in with a loop that uses VARIABLE as the
key in the hash.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
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