[prog] getting parameters into scripts

[John Clarke]

On Mon, Mar 29, 2010 at 12:07:01PM +1000, Miriam English wrote:

Hi Miriam,

> head until this morning I hit on the idea of doing something like this:
>
> for i in $@; do
>     eval "$i"
> done
[snip]
> Anybody know how to get parameters with spaces into those variables?

Well, this works the way you want, but only for parameters of the form
var=value:

    for i in "$@"
    do
        i=`echo $i|sed -e 's/=\(.*\)/="\1"/'`
        eval $i
    done

It restores quotes around everything after the equals sign before the
eval is done.  Note the quotes around $@, this is essential to get the
behaviour you want.

You could use bash's built-in pattern substitution if you want.  Instead
of the sed command, use this:

        i="${i/=/=\"}\""

(a bit ugly because bash doesn't support back-references, so the closing
 quote has to be added after the pattern substitution)

If you wanted to only eval parameters of the form var=value, try this
(bash only):

    shopt -s extglob
    for i in "$@"
    do
        case $i in
            +([[:word:]])=*)
                i=`echo $i|sed -e 's/=\(.*\)/="\1"/'`
                eval $i
                ;;
            *)
                # do whatever you want with other parameters here
                ;;
        esac        
    done

(remove the shopt and replace "+([[:word:]])=*" with "*=*" if you need
to use sh).

> Or should I just give up on trying to be a mental contortionist? :)

Think of it as a learning experience :-)


John
-- 
> Cars _are_ hardware.  If you can kick it, without it caring, it's hardware.
Funny, I always thought my boss fell into the category of "wetware."
            -- Dave Buckles