What is sleep Command And How to Use it with Example
sleep is a command-line utility that allows you to suspends the calling process for a specified time. In other words, the
sleep command pauses the execution of the next command for a given number of seconds.
sleep command is useful when used within a bash shell script, for example, when retrying a failed operation or inside a loop.
In this tutorial, we will show you how to use the Linux
How to Use the
The syntax for the
sleep command is as follows:
NUMBER may be a positive integer or a floating-point number.
SUFFIX may be one of the following:
s– seconds (default)
When no suffix is specified, it defaults to seconds.
When two or more arguments are given, the total amount of time is equivalent to the sum of their values.
Here are a few simple examples demonstrating how to use the
- Sleep for 5 seconds:
- Sleep for 0.5 seconds:
- Sleep for 2 minute and 30 seconds:
sleep 2m 30sCopy
Bash Script Examples
In this section, we’ll go over a few basic shell scrips to see how the
sleep command is used.
#!/bin/bash # start time date +"%H:%M:%S" # sleep for 5 seconds sleep 5 # end time date +"%H:%M:%S"
When you run the script, it will print the current time in
HH:MM:SS format. Then the
sleep command pauses the script for 5 seconds. Once the specified time period elapses, the last line of the script prints the current time.
The output will look something like this:
Let’s take a look at a more advanced example:
#!/bin/bash while : do if ping -c 1 ip_address &> /dev/null then echo "Host is online" break fi sleep 5 done
The script checks whether a host is online or not every 5 seconds. When the host goes online, the script will notify you and stop.
How the script works:
- In the first line, we are creating an infinite
- Then we are using the
pingcommand to determine whether the host with IP address of
ip_addressis reachable or not.
- If the host is reachable, the script will echo “Host is online” and terminate the loop.
- If the host is not reachable, the
sleepcommand pauses the script for 5 seconds, and then the loop starts from the beginning.
sleep command is one of the simplest Linux commands. It is used to pause the execution of the next command for a given amount of time.