set x 1;
if {$x == 2} {puts "$x is 2"} else {puts "$x is not 2"}
if {$x != 1} {
puts "$x is != 1"
} else {
puts "$x is 1
}
if $x==1 {puts "GOT 1"}
;# Two passes of substitution will be done on this test string
;# The initial pass replaces $y with x
;# Within the if statement, $x is replaced with 1
set y x;
if "$$y != 1" {
puts "$$y is != 1"
} else {
puts "$$y is 1"
}