passing arrays and working with arrays in BASH

[tmetro-blu-5a1Jt6qxUNc at public.gmane.org (Tom Metro)]

theBlueSage wrote:
> ------------ start code snippet --------------
> #!/bin/bash
> function search_array() {
>     index=0
>     array=( "$@" )
>     #echo ${array[@]}
>     let TCNT=${#array[@]}-1
>     LASTVAL=${array[${#array[@]}-1]}
>     while [ "$index" -lt "$TCNT" ]; do
>         if [ "${array[$index]}" = "$LASTVAL" ]; then
>             echo $index
>             return
>         fi
>         let "index++"
>     done
>     echo ""
> }
> -------- end code snippet ----------------
> 
> The result is I add the scalar to the end of the array, pass it to
> the function and then peel it off again.

It seems like you are seeking a pass-by-reference mechanism, of which 
I'm not aware of a way to do that in Bash. But there are two 
alternatives that you may consider a slight improvement:

1. When ever you have a function that has fixed arguments plus a 
variable length list, put the fixed arguments first, so you can use 
'shift' to pull them off the argument list, leaving $@ to be processed 
by your loop.

2. Emulate "pass-by-reference" by converting your list argument into a 
single string, then splitting it back into an array within your function.

  -Tom



-- 
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/