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  expres-
       sion  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
