bash: Definitions
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 'token' 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 'space', 'tab', 'newline', 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'. 
Redirections, for a list of redirection operators. Operators
contain at least one unquoted 'metacharacter'.
'process group'
A collection of related processes each having the same process
group ID.
'process group ID'
A unique identifier 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 sequence of characters treated as a unit by the shell. Words may
not include unquoted 'metacharacters'.
Info Catalog
bash: Introduction
bash: Top
bash: Basic Shell Features