From the Command Line

You can use the print or display command with the difference operator and the varfile intrinsic to perform a comparison between two versions of a variable or expression.

For example, if you saved x in the file x.var:

varsave "x.var" x

then the command

print x - varfile("x.var")

prints the difference between the current and saved values of x.

If an element is printed as 0, it is the same in both versions. If it is nonzero, its value is different in the two versions.