The Tcl command structure is very simple. It always follows the format
command arg1 arg2 ...This means that no commands can be written as infix operators, each statement must always begin with the command name and it is followed by optional arguments. Tcl commands are separated by newline characters or by semicolons:
Every Tcl commands returns a value.set a 1 set b 2; set c 3
The Tcl built-in commands sometimes recognise arguments by their prefix only, if it is unique, so for instance info patchlevel can also be written as info pa. However, we recommend to use this feature with care, as it often makes programs unreadable.