Case-statement and variables

[Wessel Baptist]

Why does this script respond whith "Wrong..." and "Right..." which I expected?

export POSSIBLE="6.6.01|6.6.02"
export CURRENT="6.6.01"
case $CURRENT in
$POSSIBLE)
echo "Right $CURRENT"
;;
(*)
echo "Wrong $CURRENT"
esac

[Bill McNAMARA_1 · Accepted solution]

why don't you switch around the 6.6.01 in the
first export which may explain it.
Who cares anyway... it works!

Bill

[Wessel Baptist]

Sorry. I typed too fast, I forgot the word "NOT".
I mean: Why does this script respond whith "Wrong..." and NOT whith "Right..." which I expected?

[John Palmer]

Hi,

I think that it fails because of the order in which the shell processes the case statement.
The first thing that it does is to split the lines into tokens that are serarated by the standard set of metacharacters:-
space tab newline ; ( ) < > | &

Later it performs parameter substitution on $POSSIBLE but this is too late for it to correctly handle the | characters.

You can force the shell to re-evaluate the command with the 'eval' statement and indeed if you try:-

eval "

"

then you get the result that you expected. Quoting of this form can cause problems though.

Hope this helps,

Regards,
John