sleep Command

Purpose

Suspends execution for an interval.

Syntax

sleep Seconds

Description

The sleep command suspends execution of a process for at least the interval specified by the Seconds parameter. The amount of time specified in the Seconds parameter can range from 1 to MAXINT (2,147,483,647) seconds.

Exit Status

This command returns the following exit values:

Item	Description
0	The execution was successfully suspended for at least Seconds seconds, or a SIGALRM signal was received.
>0	An error occurred.

Examples

To run a command after a certain amount of time has passed, enter:

(
echo  "SYSTEM SHUTDOWN IN 10 MINUTES!" | wall
sleep 300; echo "SYSTEM SHUTDOWN IN 5 MINUTES!" | wall
sleep 240; echo "SYSTEM SHUTDOWN IN 1 MINUTE!" | wall
sleep 60; shutdown
)&

This command sequence warns all users 10 minutes, 5 minutes, and 1 minute before the system is shut down.

To run a command at regular intervals, enter:
```
while true
do
 date
 sleep 60
done
```
This shell procedure displays the date and time once a minute. To stop it, press the Interrupt key sequence.