let

Perform arithmetic on shell variables.

SYNTAX
      let expression [expression]

If the last expression evaluates to 0, let returns 1; otherwise 0 is returned.

`let' is a BASH builtin command.

"Arithmetic is being able to count up to twenty without taking off your shoes." - Mickey Mouse

Related commands:

expr - Evaluate expressions
eval - Evaluate several commands/arguments
test - Evaluate a conditional expression