Bash script, case statement and sub-menus

Question

I wish to run a script with a case statement leading to choices between other lists of choices (sort of sub-menus) between scripts :

#!/bin/bash

echo "Your choice ?"
echo "1) Foo"
echo "2) Bar"
echo "3) Stuff"
read case;

case $case in

#and this is where I would like to allow 
#(here a simplified example I do not manage to code)

1) What script ?    # may I use another case statement ?
    a) Foo1;;
    b) Foo2;;
2) What script ?    # d°
    a) Bar1;;
    b) Bar2;;
    c) Bar3;;

esac

Foo1, Foo2, Bar1, Bar2 and Bar3 being in fact bash scripts, I would like to call, eg, sh Foo1 from within the script.

How must I proceed : May I include a case statement within a case statement (better than if statement, if the choices are numerous) ? And how do I call a script from within another script ?

Thanks in advance for your help

ThG

Answer 1

Dennis' answer should do what you want. Just to illustrate how to do it with functions, so as to make the script more readable:

function which_foo {
    local foo_options=("foo1" "foo2" "cancel")
    local PS3="Select foo: "

    select foo in "${foo_options[@]}"
    do
        case $REPLY in
            1) ./foo1.sh
               break ;;

            2) ./foo2.sh
               break ;;

            3) break ;;
        esac
    done
}

ACTIONS=("foo" "bar" "quit")
PS3="Select action: "

select action in "${ACTIONS[@]}"
do
    case $action in
         "foo") which_foo
                break ;;

         "bar") which_bar # Not present in this example
                break ;;

        "quit") break ;;
    esac
done

As an aside, note:

• the use of $REPLY in the case inside which_foo, which is automatically set to the number selected by the user, instead of the text of the option.
• the use of break in each case options. Without them, select puts you in a loop, so the user would be asked to enter a choice again.
• that select never changes the value of PS3 for you, so you have to do it yourself when switching between the different levels of your menu.

Answer 2

Yes, you can nest case statements. You should also consider using a select statement instead of all those echo and read statements.

options=("Option 1" "Option 2" "Option3" "Quit")
optionsprompt='Please enter your choice: '

sub1=("Option 1 sub 1" "Option 1 sub 2")
sub1prompt='Please enter your choice: '

PS3=$optionsprompt
select opt in "${options[@]}"
do
    case $opt in
        "Option 1")
            echo "you chose choice 1"
            PS3=$sub1prompt
            select sub1opt in "${sub1[@]}"
            do
                case $sub1opt in
                    "Option 1 sub 1")
                        echo "you chose choice 2"
                        ;;
                    "Option 1 sub 2")
                        echo "you chose choice 2"
                        ;;
                 esac
            done
            ;;
        "Option 2")
            echo "you chose choice 2"
            ;;
        "Option 2")
            echo "you chose choice 3"
            ;;
        "Quit")
            break
            ;;
        *) echo invalid option;;
    esac
done

The first level menu would look like this:

1) Option 1
2) Option 2
3) Option3
4) Quit
Please enter your choice:

However, that can get very hairy very quickly. It would be better to break it up into functions where the inner select/case statements are in separate functions or are abstracted so you can pass arguments to control them.

To call another script, you might want to set a variable that holds the directory. It would look something like this:

basedir=/some/path

case ...
...
    $basedir/Foo    # call the script