Very Computer

Feeling very stupid this morning and cant sort this problem out, help
would be appreciated.

Say I have the following sort of script (I know it is not right), its
for illustration purposes.

DIR1=/blob/blobby
DIR2=/blob/notblobby

for EXT in 1 2
do
DIR=$("DIR"$EXT)
echo $DIR
done

Of course, what I would like to see output is

/blob/blobby
/blob/notblobby

In the above example, it shouts bad substitution.  I have tried a number
of quoting variations without luck.
Am I barking completely up the wrong tree, is there another way to do
this?
I need the for loop though as there are other things apart from this
variable I have to manipulate.

Cheers
Aengus

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Aengus, let me reveal the Secret of All Eval ...

Inside the loop, try:

eval echo \$DIR$EXT

The eval command forces the shell to 'evaluate' meta-characters first,
before processing the line as normal.  So on the first evaluation, the
backslash is stripped, the first dollar, being protected by backslash, is
left as a dollar, but the $EXT is 'evaluated' to 1 or 2.  This gives the
shell the command:

echo $DIR1
or
echo $DIR2

Next, the shell processing this as normal, evaluating either $DIR1 or $DIR2,
and you see either

/blob/blobby
or
/blob/notblobby

Hope this helps.
Regards, Clyde

The "typeset -n <varname>" builtin exists (only in ksh93, alas) to
transparently do exactly this.

-Brian