The sleep command

I showed the sleep command earlier, let's look at that in much more detail. In general, the sleep command is used to introduce a delay in the script. For example, in the previous script if I had not used sleep the output would have scrolled off too quickly to see what was going on.

The sleep command takes a parameter indicating how long to make the delay. For example, sleep 1 means to introduce a delay of one second. Here are a few examples:

sleep 1       # sleep 1 second (the default is seconds)
sleep 1s      # sleep 1 second
sleep 1m      # sleep 1 minute
sleep 1h      # sleep 1 hour
sleep 1d      # sleep 1 day

The sleep command actually has a bit more capability that what is shown here. For more information, please consult the man page (man sleep).

Here's a script showing in more detail how sleep works:

Chapter 3 - Script 10

#!/bin/sh
#
# 5/3/2017
#
echo "script10 - Linux Scripting Book"

echo "Sleeping seconds..."
x=1
while [ $x -le 5 ]
do
 date
 let x++
 sleep 1
done

echo...