Linux / UNIX: Bash Script Sleep or Delay a Specified Amount of Time

Author: Vivek Gite

How do I pause for 5 seconds or 2 minutes in my bash shell script on a Linux or Unix-like systems?

You need to use the sleep command to add delay for a specified amount of time. The syntax is as follows for gnu/bash sleep command:
sleep NUMBER[SUFFIX]

Where SUFFIX may be:

1. s for seconds (the default)
2. m for minutes.
3. h for hours.
4. d for days.

Please note that the sleep command in BSD family of operating systems (such as FreeBSD) or macOS/mac OS X does NOT take any suffix arguments (m/h/d). It only takes arguments in seconds. So syntax for sleep command for Unix like system is:
sleep NUMBER

Examples

### To sleep for 5 days, use: ##
sleep 5d
 
#####################################################################
# BSD/Unix/macOS implementations of sleep command have required that number 
# be an integer, and only accepted a single argument without a suffix. 
# However, GNU/Linux version of sleep command accepts arbitrary floating 
# point numbers.
#####################################################################
 
### To sleep for 1.5 seconds: ##
sleep 1.5
 
## To sleep for .5 seconds: ###
sleep .5

The most common usage are as follows:

## run commmand1, sleep for 1 minute and finally run command2 ## 
command1 && sleep 1m && command2
 
## sleep in bash for loop ##
for i in {1..10}
do
  do_something_here
  sleep 5s
done
 
## run while loop to display date and hostname on screen ##
while [ : ]
do
    clear
    tput cup 5 5
    date
    tput cup 6 5
    echo "Hostname : $(hostname)"
    sleep 1
done

Sample outputs from last while loop:

Animated gif.01: Sleep command in action

sleep Command Bash Script Example

Here is a simple example:

#!/bin/bash
echo "Hi, I'm sleeping for 5 seconds..."
sleep 5  
echo "all Done."

...
...
lockdir=`echo "$cofile" | sed -e 's|[/\\:.-]|_|g'`.d
while true; do
  if mkdir "$lockdir" >/dev/null 2>&1; then
    break
  fi
  sleep 1
done
....
..
....

How can I pause my bash shell script for 5 seconds before continuing?

Use the read command:
read -p "text" -t 5
read -p "Waiting five secs for Cloudflare to clear cache...." -t 5
echo "Generating pdf file now ...."
Sample outputs:
Waiting five secs for Cloudflare to clear cache....
Generating pdf file now ....
Where,

• -p "text" : Show the text without a trailing newline before time out.
• -t N : Set time out to 5 seconds.

For more info see bash command by typing the following man command:
$ man bash
$ man sleep
$ help read

Ref: https://www.cyberciti.biz/faq/linux-unix-sleep-bash-scripting/