bash: Definitions
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1 2 Definitions
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1 These definitions are used throughout the remainder of this manual.
1
1 'POSIX'
1 A family of open system standards based on Unix. Bash is primarily
1 concerned with the Shell and Utilities portion of the POSIX 1003.1
1 standard.
1
1 'blank'
1 A space or tab character.
1
1 'builtin'
1 A command that is implemented internally by the shell itself,
1 rather than by an executable program somewhere in the file system.
1
1 'control operator'
1 A 'token' that performs a control function. It is a 'newline' or
1 one of the following: '||', '&&', '&', ';', ';;', ';&', ';;&', '|',
1 '|&', '(', or ')'.
1
1 'exit status'
1 The value returned by a command to its caller. The value is
1 restricted to eight bits, so the maximum value is 255.
1
1 'field'
1 A unit of text that is the result of one of the shell expansions.
1 After expansion, when executing a command, the resulting fields are
1 used as the command name and arguments.
1
1 'filename'
1 A string of characters used to identify a file.
1
1 'job'
1 A set of processes comprising a pipeline, and any processes
1 descended from it, that are all in the same process group.
1
1 'job control'
1 A mechanism by which users can selectively stop (suspend) and
1 restart (resume) execution of processes.
1
1 'metacharacter'
1 A character that, when unquoted, separates words. A metacharacter
1 is a 'space', 'tab', 'newline', or one of the following characters:
1 '|', '&', ';', '(', ')', '<', or '>'.
1
1 'name'
1 A 'word' consisting solely of letters, numbers, and underscores,
1 and beginning with a letter or underscore. 'Name's are used as
1 shell variable and function names. Also referred to as an
1 'identifier'.
1
1 'operator'
11 A 'control operator' or a 'redirection operator'. ⇒
Redirections, for a list of redirection operators. Operators
1 contain at least one unquoted 'metacharacter'.
1
1 'process group'
1 A collection of related processes each having the same process
1 group ID.
1
1 'process group ID'
1 A unique identifier that represents a 'process group' during its
1 lifetime.
1
1 'reserved word'
1 A 'word' that has a special meaning to the shell. Most reserved
1 words introduce shell flow control constructs, such as 'for' and
1 'while'.
1
1 'return status'
1 A synonym for 'exit status'.
1
1 'signal'
1 A mechanism by which a process may be notified by the kernel of an
1 event occurring in the system.
1
1 'special builtin'
1 A shell builtin command that has been classified as special by the
1 POSIX standard.
1
1 'token'
1 A sequence of characters considered a single unit by the shell. It
1 is either a 'word' or an 'operator'.
1
1 'word'
1 A sequence of characters treated as a unit by the shell. Words may
1 not include unquoted 'metacharacters'.
1