DEFINITIONS The following definitions are used throughout the rest of this document:

• blank → A space or tab.
• word → A sequence of characters considered as a single unit by the shell. Also known as a token.
• name → A word consisting only of alphanumeric characters and underscores, and beginning with an alphabetic character or an underscore. Also referred to as an identifier.
• metacharacter →A character that, when unquoted, separates words. One of the following: | & ; ( ) < > space tab
• control operator → A token that performs a control function. It is one of the following symbols: || & && ; ;; ( ) | <newline>
• SIMPLE COMMANDS
• PIPELINES
• REDIRECTION
• SIMPLE COMMAND EXPANSION
• COMMAND EXECUTION
• SIGNALS
• JOB CONTROL
• READLINE