I am trying to write a shell script which has a part where I have to use some kind of loop to execute some commands if condition satisfy.
I want to understand what is the best way to approach this problem.

Lets say there are 3 flags

#export flag1=1
#export flag2=1
#export flag3=1

These are commented in the beginning. While running the script, I want to enable these flags one after the other.

So for that I have written a if else loop in such way.

if [[ -n ${flag1} ]]; then
    #some commands
elif [[ -n "${flag2}" ]]; then
    #some commands
elif [[ -n ${flag3} ]]; then
    #some commands
else
    #some commands
fi

But, when I enable flag1 it goes to else loop and it’s giving different result than expected.

What’s the best way to approach this issue?

Should I use case instead of if else loop ?