TCL : Concatenate a variable and a string

Question

Assume we have a variable \'a\' set to 12345 :

set a 12345

Now how do i set a new variable \'b\' which contains the value of \'a\' and anot

Answer 1

other option is to use set command. since set a gives value of a we can use it to set value of b like below

set b [set a]9876