if(3Tcl)

NAME
     if - Execute scripts conditionally

SYNOPSIS
     if expr1 ?then? body1 elseif expr2 ?then? body2 elseif ... ?else? ?bodyN?


DESCRIPTION
     The if command evaluates expr1 as an expression (in the same way that
     expr evaluates its argument).  The value of the expression must be a
     boolean (a numeric value, where 0 is false and anything is true, or a    |
     string value such as true or yes for true and false or no for false); if
     it is true then body1 is executed by passing it to the Tcl interpreter.
     Otherwise expr2 is evaluated as an expression and if it is true then
     body2 is executed, and so on.  If none of the expressions evaluates to
     true then bodyN is executed.  The then and else arguments are optional
     ``noise words'' to make the command easier to read.  There may be any
     number of elseif clauses, including zero.  BodyN may also be omitted as
     long as else is omitted too.  The return value from the command is the
     result of the body script that was executed, or an empty string if none
     of the expressions was non-zero and there was no bodyN.


KEYWORDS
     boolean, conditional, else, false, if, true