приостановить выполнение на интервал (suspend execution for an interval)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
sleep — suspend execution for an interval
Синопсис (Synopsis)
sleep time
Описание (Description)
The sleep utility shall suspend execution for at least the
integral number of seconds specified by the time operand.
Параметры (Options)
None.
Операнды (Operands)
The following operand shall be supported:
time A non-negative decimal integer specifying the number of
seconds for which to suspend execution.
Стандартный ввод (Stdin)
Not used.
Входные файлы (Input files)
None.
Переменные окружения (Environment variables)
The following environment variables shall affect the execution of
sleep:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base
Definitions volume of POSIX.1‐2017, Section 8.2,
Internationalization Variables for the precedence of
internationalization variables used to determine the
values of locale categories.)
LC_ALL If set to a non-empty string value, override the values
of all the other internationalization variables.
LC_CTYPE Determine the locale for the interpretation of
sequences of bytes of text data as characters (for
example, single-byte as opposed to multi-byte
characters in arguments).
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Асинхронные события (Asynchronous events)
If the sleep utility receives a SIGALRM signal, one of the
following actions shall be taken:
1. Terminate normally with a zero exit status.
2. Effectively ignore the signal.
3. Provide the default behavior for signals described in the
ASYNCHRONOUS EVENTS section of Section 1.4, Utility
Description Defaults. This could include terminating with a
non-zero exit status.
The sleep utility shall take the standard action for all other
signals.
Стандартный вывод (Stdout)
Not used.
Стандартный вывод сообщений (Stderr)
The standard error shall be used only for diagnostic messages.
Выходные файлы (Output files)
None.
Расширенное описание (Extended description)
None.
Статус выхода (Exit)
The following exit values shall be returned:
0 The execution was successfully suspended for at least time
seconds, or a SIGALRM signal was received. See the
ASYNCHRONOUS EVENTS section.
>0 An error occurred.
Последствия ошибок (Consequences of errors)
Default.
The following sections are informative.
Использование в приложениях (Application usage)
None.
Примеры (Examples)
The sleep utility can be used to execute a command after a
certain amount of time, as in:
(sleep 105; command) &
or to execute a command every so often, as in:
while true
do
command
sleep 37
done
Обоснование (Rationale)
The exit status is allowed to be zero when sleep is interrupted
by the SIGALRM signal because most implementations of this
utility rely on the arrival of that signal to notify them that
the requested finishing time has been successfully attained. Such
implementations thus do not distinguish this situation from the
successful completion case. Other implementations are allowed to
catch the signal and go back to sleep until the requested time
expires or to provide the normal signal termination procedures.
As with all other utilities that take integral operands and do
not specify subranges of allowed values, sleep is required by
this volume of POSIX.1‐2017 to deal with time requests of up to
2147483647 seconds. This may mean that some implementations have
to make multiple calls to the delay mechanism of the underlying
operating system if its argument range is less than this.
Будущие направления (Future directions)
None.
Смотри также (See also)
wait(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables
The System Interfaces volume of POSIX.1‐2017, alarm(3p),
sleep(3p)
