Shell Programming and Scripting

Hi everyone, first post here so please be gentle :-)

I normally likle to script in Bourne Shell simply for guarenteed compatibility across any system I might run across but this latest problem has me stumped.

Arrays is a rather significant construct missing from sh and after finding a way to 'fudge' them using eval I thought I found the solution to my problem. However I cant seem to get it to work in all circumnstances. I wont go into all the details, I'll just give you a trivial example.

x=0
eval DATA${x}="element$x"
x=`expr $x + 1`
eval DATA${x}="element$x"
x=0
eval echo \$DATA$x
x=`expr $x + 1`
eval echo \$DATA$x

This correct echos "element0" and "element1". However what I cannot get to work is using the eval within a test construct. What I would like to do is this:

if [ "`eval echo \$DATA$x`" = "element0" ]
then
echo element 0 found
fi

but it just doesnt work. the eval works fiune standalone but withing back quotes it doesn't. I am obviously misunderstanding something as to how back quote execution, eval, or possibly both work. So I dont know even if its possible to do this at all.

I've tried all sensible (and not so sensible) combinations of quotationa dn escaping to no avail.

Any help appreciated.

Sean Timmins

Code:

if eval [ "\$DATA$x" = "element0" ]; then echo element 0 found; fi

or

Code:

eval [ "\$DATA$x" = "element0" ]&& echo element 0 found

Gah! Thanks for that r2007, it works fine now.

I had to escape all the double quotes in the test because I was actually testing for the presence of a null string but other than that its good.