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2 Definitions
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These definitions are used throughout the remainder of this manual.

'POSIX'
     A family of open system standards based on Unix.  Bash is primarily
     concerned with the Shell and Utilities portion of the POSIX 1003.1
     standard.

'blank'
     A space or tab character.

'builtin'
     A command that is implemented internally by the shell itself,
     rather than by an executable program somewhere in the file system.

'control operator'
     A 'word' that performs a control function.  It is a 'newline' or
     one of the following: '||', '&&', '&', ';', ';;', '|', '(', or ')'.

'exit status'
     The value returned by a command to its caller.  The value is
     restricted to eight bits, so the maximum value is 255.

'field'
     A unit of text that is the result of one of the shell expansions.
     After expansion, when executing a command, the resulting fields are
     used as the command name and arguments.

'filename'
     A string of characters used to identify a file.

'job'
     A set of processes comprising a pipeline, and any processes
     descended from it, that are all in the same process group.

'job control'
     A mechanism by which users can selectively stop (suspend) and
     restart (resume) execution of processes.

'metacharacter'
     A character that, when unquoted, separates words.  A metacharacter
     is a 'blank' or one of the following characters: '|', '&', ';',
     '(', ')', '<', or '>'.

'name'
     A 'word' consisting solely of letters, numbers, and underscores,
     and beginning with a letter or underscore.  'Name's are used as
     shell variable and function names.  Also referred to as an
     'identifier'.

'operator'
     A 'control operator' or a 'redirection operator'.  Note:
     Redirections, for a list of redirection operators.

'process group'
     A collection of related processes each having the same process
     group ID.

'process group ID'
     A unique identifer that represents a 'process group' during its
     lifetime.

'reserved word'
     A 'word' that has a special meaning to the shell.  Most reserved
     words introduce shell flow control constructs, such as 'for' and
     'while'.

'return status'
     A synonym for 'exit status'.

'signal'
     A mechanism by which a process may be notified by the kernel of an
     event occurring in the system.

'special builtin'
     A shell builtin command that has been classified as special by the
     POSIX standard.

'token'
     A sequence of characters considered a single unit by the shell.  It
     is either a 'word' or an 'operator'.

'word'
     A 'token' that is not an 'operator'.


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