The document discusses pattern matching in UNIX and shell programming. It defines a pattern as using ordinary characters and metacharacters like asterisk (*) to match filenames. It lists common wild-card metacharacters like asterisk (*) to match any number of characters, question mark (?) to match a single character, and brackets ([]) to match single characters in a range or set. It also discusses the mechanism of process creation in UNIX using the fork, exec, and wait system calls. The fork call creates a child process copy, exec overwrites the child process with a new program, and wait allows the parent to pick up the child's exit status.