This initializes the variables as you can see in the output:
$ read_foo
/home/
/dev/sda1
1GB
Now you can prepare the zenity/dialog screen with existing values pre-populated and allow user to change them. Once the user is done, you can write it back using below (assuming user has write permissions):
thanks just what i was looking for . now just how i can implement it , it's one thing knowing how to do it it's another thing doing it a real world script
I suggest you use a sample config file with only one parameter. Focus on finalizing the design with that. That will give you enough understanding to proceed.