[prog] Shell question...

[John Clarke]

On Sat, Dec 11, 2004 at 03:18:44 +0100, Riccarda Cassini wrote:
> > 
> > You have way too much time on your hands :-)
> 
> Heh, I'd rather call it applied ISO 9000 / QA testing ;-)

Your boss might believe you, but you and I both know I'm right :-)

> >     echo "$1='$VALUE'"
> 
> Then, what about bl'a ?  ;-)
> 
> This may seem like just being silly.  Well, it is.  However, there's a
> kernel of truth in it...  Is there an (easy) way to make this approach
> robust against any kind of special characters, like " ' $ \ etc.?

Good question.  I think it's possible, but it's not easy to handle all
metacharacters anywhere in the string.  Not in shell anway, because
there isn't a great range of substitution available -- bash has
${var//pattern/replacement} but I couldn't get it to do all characters.
You also have to protect against several levels of shell interpolation
(the outer script, read_vars.sh, and the eval) which, as you've already
discovered, soon needs way too many backslashes.  I played with it for a
minute or two and found a couple of different ways to handle quotes, but
I couldn't make it do $.  Eventually you decide it's easier to do it in
perl or C :-)

> Probably not all that relevant in my case, but you know, in general,
> when it doesn't cost much, it's always better to do things the right
> way *before* you have a raging client on the phone...

That's true, but if you was done right the first time you wouldn't be
trying to fix it now, would you?


Cheers,

John
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