Change value of same variables in multiple code files - replace

Question

I have multiple f90 files that contain the same variables
integer,parameter :: ilatmin = 0.5
integer,parameter :: ilatmax = 180
integer,parameter :: ilonmin = 0.5
integer,parameter :: ilonmax = 360
I would like to write shell script or a makefile where I specify the value of each variable and that loop through each .f90 file and update the values for each variable.
I though about using a search and replace like in this example Linux find and replace but was wondering if it's a good idea to use sed in a bash script.

Answer 1

Why don't you put those parameters into a module that you use inside the *.f90 files? It could look like:
module myParameters
implicit none
integer,parameter :: ilatmin = 0.5
integer,parameter :: ilatmax = 180
integer,parameter :: ilonmin = 0.5
integer,parameter :: ilonmax = 360
end module
In your code you then can include that module, e.g.
subroutine foo
use myParameters, only: ilatmin, ilatmax, ilonmin, ilonmax
! ...
end subroutine
Now you just need to change the module myParameters...
To your question... Using sed this could look like:
for i in *.f90; do
sed -i -e 's/ilatmin = .*$/ilatmin = XYZ/g' \
-e 's/ilatmax = .*$/ilatmax = XYZ/g' \
-e 's/ilonmin = .*$/ilonmin = XYZ/g' \
-e 's/ilonmax = .*$/ilonmax = XYZ/g' $i
done