оболочка, стандартный интерпретатор командного языка (shell, the standard command language interpreter)
Асинхронные события (Asynchronous events)
The sh utility shall take the standard action for all signals
(see Section 1.4, Utility Description Defaults) with the
following exceptions.
If the shell is interactive, SIGINT signals received during
command line editing shall be handled as described in the
EXTENDED DESCRIPTION, and SIGINT signals received at other times
shall be caught but no action performed.
If the shell is interactive:
* SIGQUIT and SIGTERM signals shall be ignored.
* If the -m option is in effect, SIGTTIN, SIGTTOU, and SIGTSTP
signals shall be ignored.
* If the -m option is not in effect, it is unspecified whether
SIGTTIN, SIGTTOU, and SIGTSTP signals are ignored, set to the
default action, or caught. If they are caught, the shell
shall, in the signal-catching function, set the signal to the
default action and raise the signal (after taking any
appropriate steps, such as restoring terminal settings).
The standard actions, and the actions described above for
interactive shells, can be overridden by use of the trap special
built-in utility (see trap(1p) and Section 2.11, Signals and
Error Handling).
