Expressions are the basic building blocks of any programming language. They form its core logic. Expressions evaluate to a value that we can test, print, or pass to any function. They are also used to assign a new value to a variable. AWK expressions are made up of operators and operands, which consist of constants, variables, regular expressions, and function calls.
In this chapter, we will cover the following topics:
- AWK variables and constants
 - Expressions using binary arithmetic operators
 - Expressions using assignment operations
 - Expressions using increment and decrement operators
 - Expressions using relational operators
 - Expressions using logical operators
 - Expressions using ternary operators
 - Unary arithmetic expressions
 - Exponential expressions
 - String concatenation
 - Regular expression operators