
 let  evaluate arithmetic expressions

 let [ options ] [expr ...]

 let evaluates each expr in the current shell environment as an arithmetic expression using ANSI C syntax. Variables names are
shell variables and they are recursively evaluated as arithmetic expressions to get numerical values.
 let has been made obsolete by the ((...)) syntax of ksh(1) which does
not require quoting of the operators to pass them as command arguments.

 0
 The last expr evaluates to a nonzero value.
 >0
 The last expr evaluates to 0 or an error occurred.

 expr(1), test(1), ksh(1)

 version
 let (AT&T Research) 20000402
 author
 David Korn <dgkorn@gmail.com>
 copyright
 Copyright © 19822010 AT&T Intellectual Property
 license
 http://www.opensource.org/licenses/cpl1.0.txt