# Logic Expressions

Learn what boolean expressions are and how they work.

## We'll cover the following

The search conditions of the `find`

utility are **boolean expressions**. A boolean expression is a programming language statement. It produces a boolean value when evaluated that equals either `true`

or `false`

.

The `find`

condition is a statement of the utilityâ€™s language. It produces the `true`

value if the found object meets its requirement. Otherwise, the condition produces `false`

. If there are several conditions in the `find`

call, they make a single compound boolean expression.

## Logical operators

When we considered the binary numeral system, we already were introduced to boolean algebra. This section of mathematics studies **logical operators**. They differ from the arithmetic operations: addition, subtraction, multiplication, and division.

We can apply a logical operator to boolean values or expressions. Using an arithmetic operation doesnâ€™t make sense in this case. Addition or subtraction is trivial for boolean values. It yields nothing. When we apply a logical operator, we get a condition with strict evaluation rules. This way, we previously wrote search conditions for the `find`

utility. When we combine several conditions, we get a program with complex behavior.

### Operand

An **operand** is an object of a logical operator. Boolean values and expressions can be operands.

## Programming a robot

Letâ€™s consider Boolean expressions using an example. For simplicity, the example is not related to the `find`

utility or Bash. Letâ€™s imagine that we are programming a robot for a warehouse. Its job is to move boxes from point A to point B. We can write the following straightforward algorithm for the robot:

- Move to point A.
- Pick up the box at point A.
- Move to point B.
- Put the box at point B.

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