Using the let command for arithmetic

We can use the bash built-in command let for performing arithmetic operations. To get more information about let, type the following:

    $ help let
  

This should produce the following output of this command:

Let's start using the let command:

    $ value=6
    $ let value=value+1
    $ echo $value
    7
    $ let "value=value+4"
    $ echo $value
    11
    $ let "value+=1"
    #above expression evaluates as value=value+1
    $ echo $value
    12  

A summary of operators available with the let command follows:

  • Operation: Operator
  • Unary minus: -
  • Unary plus: +
  • Logical NOT: !
  • Bitwise NOT (negation): ~
  • Multiply: *
  • Divide: /
  • Remainder: %
  • Subtract: -
  • Add: ...

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