bash character substitution? Need help

[Grant Cullen]

Madison, the following will give the basic parsing.

Good luck

#!/bin/bash
X='00:11:22:33:44:55>21,53,80-85'
MAC=${X,1,17}
[ ${#X} -gt 18 ] &&
 {
  # we have ports - length greater than 18
  IFS=','
  for PORT in ${x:18}
   do
    echo "iptable entry with port " $PORT
   done
 } ||
 {
  # no ports
  echo "iptable entry without ports"
 }

Grant Cullen
JADALL Consulting Ltd.
grant.cullen-rieW9WUcm8FFJ04o6PK0Fg at public.gmane.org
416-706-4447

-----Original Message-----
From: owner-tlug-lxSQFCZeNF4 at public.gmane.org [mailto:owner-tlug at ss.org]On Behalf Of Madison
Kelly
Sent: Friday, February 06, 2004 12:40
To: tlug-lxSQFCZeNF4 at public.gmane.org
Subject: [TLUG]: bash character substitution? Need help


Hi all,

   I am working on an iptables bash script but am handicapped by not
being a programmer (or, just barely being one). Anyway, I've been able
to figure out how to take a string and read out variables based on a
character to split on but now what I need it to read a value into the
same variable over and over again based on the split. Here is my
specific issue:

I have the variable:

# Enter as (MAC address)>Port(-range),Port(-range),..,Port(-range)
TRUSTED_IB_TCP=00:11:22:33:44:55>21,53,80-85

   Now I want to check and see if ports are defined. If not, allow all
ports from the given MAC address. If so, read out the ports one after
another in a 'for/while' style loop splitting on the ','. Then inside
each of those, split on '-' and check to see if there is a value after
the '-'.

   The problem is, I know how to split on the ',' (IFS=',' ...) but this
doesn't seem like it is going to help me because I want to run a
'for/while' loop for each value, not assign new variables based on the
split (like I have done so far). Is there some way to substitute the ','
with ' ' and then do a 'for/while' loop?

   I am Googling now but I am having trouble finding the answer. I am
hoping someone here might be able to point me in the right direction.
Thanks!

Madison

PS - If it will help, I'll post what I have of the relevant parts of the
script.

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--
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TLUG requests: Linux topics, No HTML, wrap text below 80 columns
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