Regular expression as a variable

Shell Programming and Scripting
1

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

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

Desired output:

echo $LOWCASE2

Should print out a through to z

2

No, it should not - it should show

[ a-z ]

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

3

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

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).

4

Yeah that worked nicely. Thanks.