LinuxSA Mailing list archives

  From: Jake Hawkes <jake@infinitylimited.net>
  To  : Michael Kratz <michael_kratz@hotmail.com>
        LinuxSA Mailing List <linuxsa@linuxsa.org.au>
  Date: Tue, 27 Feb 2001 03:15:32 +0000

Re: pppd reconnect script

Michael Kratz wrote:
> 
> Hi Jake, thanks for your input, I am trying hard to understand this script
> but it is kinda a little over my head, how does it work??

Michael, I took the liberty of cc'ing the list. Maybe someone else will
gain something.


> so where would i add the bit like 'pppd call provider' I dont use the ppp0up
> thing i dont understand that either!!!! pretty dumb eh! I ve only been
> messing with linux since the installfest.
> 
> >so...
> >
> >#!/bin/bash
> >ping -c1 1.1.1.1

here, 1.1.1.1 is the ip of your ppp peer. when you do a ifconfig, you
will see a lines like this:
ppp0      Link encap:Point-to-Point Protocol  
          inet addr:166.72.64.158  P-t-P:166.72.52.11 
Mask:255.255.255.255

so, I would replace 1.1.1.1 with 166.72.52.11

whenever you run a command, it will return a status. This way, scripts
can tell if the program had an error or not. This is always stored in
the assumed variable $? in bash.

(An assumed variable is one that you do not define, and is usually set
by something other than your code)

> >
> >STATUS=$?

I store the value of the variable here for readability.

> >
> >echo "$STATUS returned"

a debug message

> >
> >case $STATUS in

a case (or switch) statement. This allows me to test the value of the
variable against many values, unlike an "if" statement, which only tests
the value against one value[1].

> >     0)
> >         echo "next host in route alive"
> >         ;;

here, I say "if the value of status is 0, the print this line, and then
jump to the end of the case statement.

> >     1)
> >         echo "no packets returned"
> >         ;;

here, I say "if the value of status is 1, the print this line, and then
jump to the end of the case statement.


> >     2)
> >         echo "there was an error"
> >         ;;

same

> >     *)
> >         echo "I dunno"


here I say, if I have not had any matches yet, then print this line

> >esac

this is the end of the case statement. When I say "jump to the end of
the case statement", here is where it jumps to.

you can put any number of commands in the case statements. so, you would
put:


	1)
	   echo "link dead, initiating redial";
	   killall pppd
	   pppd call provider
	   ;;


be aware that the ;; is important. it signifies the end of that block of
code, it is particular to case() statements in bash scripts.


I reckon that you might be using debian, or at least something without
"ifup" which I think is redhat (and so Mandrake to I think).

any debian-ers out there know the best way to initiate a redial? I
haven't looked to see if it is pppd that does the redial of the ifup
script.

--
Jake Hawkes B.Eng, (CSE)

Sleep is good. It'll keep you from going psychotic.

-- 
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