You do not change the value of a variable "in the same time" inside another script. Scripts share the workspace (list of variables) with their callers. Then a modification of a variable concerns all future processing of it in the caller of other scripts, which run afterwards. Consider, that calling a script is equivalent to inserting the contents of the script file in the caller. There are some differences in modern Matlab versions concerning locally defined function, e.g. in the /private subfolders, but the main idea is correct.
You can imagine that it has been severe drawbacks, if a modification in one script concerns all following code. Example:
script1
script2
sum = 1:10
disp(sum(1:5))
If you now see script2 only, it seems strange, why it does not reply the sum, but treats "sum" as a variable.
Therefore scripts are not useful and reliable for productive code. Use functions instead to keep the workspace clean and to limit the effect of changes to the locally seen function. Global variables have similar drawbacks and it is a good programming practice to avoid using them. They impede the debugging and confuse the readers.
[EDITED] You have written in your comments, that one of the "scripts" is a function. Then use the standard inputs and outputs to share data with other functions. This is clean, reliable and efficient. It is a good programming practice from the view point of debugging, maintaining and expanding the code. You can e.g. edit the internal details of a function without any side-effects on other functions, as long as the inputs and outputs are kept.
Example:
function main
A = 1;
B = 2;
[A, B] = func1(A, B)
A = func2(A, B)
[A, B] = func1(A, B)
end
function [A, B] = func1(A, B)
A = A * 2;
B = A + B;
end
function A = func2(A)
A = -A;
end
Now func2 does not have an "immediate" effect to the value of A in func1. But the result is forwarded to the caller and available in func1 as soon as it is needed. This has the advantage, that you can track all changes of the contents of A. You can know exactly by seeing the code, where changes are made and where to fix the code in case of a bug. This is a massive advantage compared to scripts, global variables or the bad assignin methods.
