These definitions are used throughout the remainder of this
manual. 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. A space or tab character. A command that
is implemented internally by the shell itself, rather than by an
executable program somewhere in the file system. token that
performs a control function. It is a or one of the following:
‘||’, ‘&&’, ‘&’, ‘;’, ‘;;’, ‘|’, ‘|&’, ‘(’, or ‘)’. The value
returned by a command to its caller. The value is restricted to
eight bits, so the maximum value is 255. 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. A string of characters used to
identify a file. A set of processes comprising a pipeline, and
any processes descended from it, that are all in the same
process group. A mechanism by which users can selectively stop
(suspend) and restart (resum