If a variable has a value, such as
and you set a second variable to the first variable
the new variable will have the same value as the first; in this case b will be equal to 1. If you later give the first variable a new value;
the new value will still have the old value, in this case, b will still be equal to 1.
The CopyVar command will copy one variable to another without evaluating the first variable; the new variable will simply be a copy of the first. With a having the value of 5, as above, the command
will make c a copy of the variable a, so it will have the value 5 also. If you now change the value of a
then the value of c will also change; here, c will now have the value 10.