Shell Programming and Scripting

I'm trying to use a series of regular expressions as variables but can't get it to behave properly.
You can see below what I'm trying to do.
Here with lowercase a-z and the same with uppercase, numbers 0-9 and again with a set of special characters, without having to type out every single character.
All variations on the below example

Code:

echo -ne "Use a-z (Lowercase) y/n: "
read UPCASE
    case $LOWCASE in
        [yY])
        LOWCASE2='[ a-z ]'
        ;;
        
        [nN])
        echo
        ;;
    esac
echo

Desired output:

Code:

echo $LOWCASE2

Should print out a through to z

No, it should not - it should show

Code:

[ a-z ]

You have to apply the regex to some other string using something like sed or perl. Then echo the new string

While you're reading UPCASE you're evaluating LOWCASE which might not give the desired results.
To assign a series of chars to a variable, try sth like

Code:

L=$(echo {a..z})
echo $L
a b c d e f g h i j k l m n o p q r s t u v w x y z

in recent shells (bash, ksh).

Yeah that worked nicely. Thanks.