The if command is rather a conditional branch than what one usually calls an if. Its syntax is
if var op number goto label
where the expression must be a simple comparison between one of the variables $errlvl, $locip, and $rmtip. The second operand must be an integer number; the operator op may be one of ==, !=, <, >, <=, and >=.
The goto command makes the execution of the script continue at the line following that bearing the label. A label must occur as the very first token on the line, and must be followed immediately by a colon.