[Techtalk] Bash functions with user-defined parameters

[Conor Daly]

On Mon, Apr 28, 2003 at 05:52:59AM -0700 or so it is rumoured hereabouts, 
Berenice thought:
> I've been messing around with bash and want to create a function that
> takes two different integers and increments the first integer by 1,
> until the first integer is the same as the second integer.  Eg: if
> there are 2 numbers, 1 and 4, add 1 to the first number until it
> becomes 4.  
> 
> Now I can do this interactively like this:
> 
> #!/bin/bash
> echo "Enter 2 numbers:"
> read num1 num2
> while [ $num1 -le  $num2 ]
> do
>   echo $num1
>   num1=$(( $num 1 + 1 ))
> done
>   
> But I'm having trouble making it into a function that executes by
> typing the function name with parameters, eg: myfunction 1 4. Here's
> what I've done so far:
> 
> 
> #!/bin/bash
> myfunction()
> {
> while [ $1 -le $2 ]
> do
>  echo $1
>  #problem here...$(( $1 + 1 ))
> done
> }
> 
> 
> The problem is with the $(( $1 + 1 )) because you can't do $1=$(( $1
> + 1 )).  Is there a way to fix this, or should I forget about using
> $1 and $2?

how about:

num1=$1
while [ $num1 -le $2 ]
do
  echo $num1
  num1=$(( $num1 + 1 ))
  # I think this works too...  num1=$(( $num1++ ))
done

Now, if you wanted to _change_ the value of $1 in the calling function,
it's a different matter...

Conor

-- 
Conor Daly <conor.daly at oceanfree.net>

Domestic Sysadmin :-)
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