how to change temperature boundary condition for every iteration in text file and write a new text file?

** BOUNDARY CONDITIONS
** 
** Name: Surf_temp1 Type: Temperature
*Boundary
Surf_temp_Set-1, 11, 11, 100.
** Name: Surf_temp2 Type: Temperature
*Boundary
Surf_temp_Set-2, 11, 11, 100.
** Name: Surf_temp3 Type: Temperature
*Boundary
Surf_temp_Set-3, 11, 11, 100.
** Name: Surf_temp4 Type: Temperature
*Boundary
Surf_temp_Set-4, 11, 11, 200.

As I am doing parametric study of thermal problem for which I am calling abaqus using matlab. It is iterative technique. I want to change 4th boundary condition Surf_temp_Set-4, 11, 11, 200.(temperature=200) for every iteration. I give random initial guess for temperature and this goes through the iterative code written in matlab, temperature increases or decreases until it satisfies objective function of iterative technique. For this I need to update temperature in input file of abaqus