sleep (Unix)

sleep is a Unix command line program that suspends program execution for a specified time. The sleep instruction suspends the calling process for at least the specified number of seconds (the default), minutes, hours or days.

Usage

 sleep number

Where number is an integer number to indicate the time period in seconds. Some implementations may support floating point numbers.

Options

None.

Examples

 sleep 30

Causes the current terminal session to wait 5 seconds.

 sleep 18000

Causes the current terminal session to wait 5 hours

GNU sleep specific Examples

 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.

 sleep 5h; sleep 30m

Sleep 5 hours, then sleep another 30 minutes .

The GNU Project'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 Linux.

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 a large file.

External links

sleep – Commands & Utilities Reference, The Single UNIX® Specification, Issue 7 from The Open Group

Unix command-line interface programs and shell builtins

File system	cat chmod chown chgrp cksum cmp cp dd du df file fsck fuser ln ls mkdir mount mv pax pwd rm rmdir split tee touch type umask

Processes	at bg chroot cron fg kill killall nice pgrep pkill ps pstree time top

User environment	clear env exit finger history logname mesg passwd su sudo uptime talk tput uname w wall who whoami write

Text processing	awk banner basename comm csplit cut diff dirname ed ex fmt fold head iconv join less more nl paste printf sed sort spell strings tail tr uniq vi wc xargs yes

Shell builtins	alias cd echo test unset wait

Networking	dig host ifconfig inetd netcat netstat nslookup ping rdate rlogin route ssh traceroute

Searching	find grep locate whatis whereis

Documentation	apropos help man

Miscellaneous	bc dc cal expr lp od sleep true and false

List of Unix commands

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