my lame attempt at a shell script...

[Eric F Crist]

On Jan 6, 2005, at 7:28 PM, Tom Vilot wrote:

> Eric F Crist wrote:
>
>>
>> First off, thanks again for all the help you've offered thus far.  
>> That being said, I'm having a problem with variables in a function.  
>> The code I'm having a problem with is:
>>
>> setup_loopback () {
>>         ${fwcmd} add ${rulenum1} pass all from any to any via lo0; 
>> ${rulenum1}=`expr $rulenum1 + 50`
>>         ${fwcmd} add ${rulenum1} deny all from any to 127.0.0.0/8; 
>> ${rulenum1}=`expr $rulenum1 + 50`
>>         ${fwcmd} add ${rulenum1} deny ip from 127.0.0.0/8 to any; 
>> ${rulenum1}=`expr $rulenum1 + 50`
>> }
>>
>> The output of this, when run, is:
>>
>> 00050 allow ip from any to any via lo0
>> 50=100: not found
>> 00050 deny ip from any to 127.0.0.0/8
>> 50=100: not found
>> 00050 deny ip from 127.0.0.0/8 to any
>> 50=100: not found
>>
>> This tells me that it's doing the math correctly, but it's not 
>> reassigning the calculated value back to the variable.
>>
>> Any pointers?
>
>
> this is a very common mistake and is one of those things about sh and 
> bash that drives me batty, too.
>
> You're thinking like perl. :c)
>
> Stripping it down to a test script, I have this:
>
> -----
> rulenum=50
>
> rulenum=`$rulenum + 50`
>
> echo $rulenum

What is the point of the { } around some variables?

_______________________________________________________
Eric F Crist                  "I am so smart, S.M.R.T!"
Secure Computing Networks              -Homer J Simpson
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