This section provides information on pattern matching and action statement. The following topics are covered:

The main part of a script is a sequence of pattern-action statements.

The pattern comes first, and then the action. Either the pattern or action may be missing in a statement. If the pattern is missing, the action will be executed for every single input line. A pattern with a missing action does nothing. Since the pattern or action may be missing, action statements are enclosed in {and} to distinguish them from patterns.