|if the order of lines in .ini does not matter then i think it can be done..may be someone have better idea as well..|
suppose .ini contents below..
name = test
number = 7
phone = 456
and you want to change the value of number .from 7 to 9
lets take a look at the steps ..
serach for string number and get the exact value using a for loop.
set /p value="enter the value to change" :
find /v %value% >tempfile.ini
set /p newvalue= "enter the new value for %value% :
echo %value% = %newvalue% >>tempini.ini
type tempini.ini >filename.ini