7.1. Filenames Versus Patterns

Metacharacters used in pattern matching are different from metacharacters used for filename expansion (see Chapter 6). However, several metacharacters have meaning for both regular expressions and for filename expansion. This can lead to a problem: the shell sees the command line first, and can potentially interpret an unquoted regular expression metacharacter as a filename expansion. For example, the command:

    $ grep [A-Z]* chap[12]