Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
A computer program may sleep, which places it into an inactive state for a period of time. Eventually the expiration of an interval timer, or the receipt of a signal or interrupt causes the program to resume execution.- Usage :...
program execution for a specified period of time.
The sleep instruction suspends the calling process
Process (computing)
In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system , a process may be made up of multiple threads of execution that execute instructions concurrently.A computer program is a...
for at least the specified number of seconds (the default), minutes, hours or days.
In computing, floating point describes a method of representing real numbers in a way that can support a wide range of values. Numbers are, in general, represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16...
number, and suffix is an optional suffix to indicate the time period. It has no real use.
Options
--help display this help and exit --version output version information and exit
Examples
sleep 5
Causes the current terminal session to wait 5 seconds. The default unit is seconds.
sleep 5h
Causes the current terminal session to wait 5 hours
sleep 3h ; mplayer foo.mp3
Wait 3 hours then play foo.mp3
Note that sleep 5h30m and sleep 5h 30m are illegal since sleep takes only one value and unit as argument. However, sleep 5.5h is allowed. Consecutive executions of sleep can also be used.
The GNU Project is a free software, mass collaboration project, announced on September 27, 1983, by Richard Stallman at MIT. It initiated GNU operating system development in January, 1984...
's implementation of sleep (part of coreutils) allows the user to pass multiple arguments, therefore sleep 5h 30m (a space separating hours and minutes is needed) will work on any system which uses GNU sleep, including GNU
GNU
GNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
.
Possible uses for sleep include scheduling tasks and delaying execution to allow a process to start, or waiting until a shared network connection most likely has few users to wget
Wget
GNU Wget is a computer program that retrieves content from web servers, and is part of the GNU Project. Its name is derived from World Wide Web and get...
a large file.
The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.
