read timeout in scripting

The command read is used in scripting to accept a value for a variable from the user.

The default operation of read is to wait infinetly for the user to enter a value. This behavour can be changed and read can be made to wait for a specific time only and abort after that.
This can be done by using the option "-t" with read i.e.

read -t 5 var

This will make read to wait for 5 seconds before aborting.
The script below shows how to use the option.

read_timeout.sh

#!/bin/bash var=0 read -t 5 var if [ $var==0 ] then echo "Please enter with in 5 seconds" fi

The above script waits for 5 seconds for the user to enter a value,if the user fails to do so the script will continue to run and throw an error message.

Save it,give it execute permissions and execute it

$ chmod 777 read_timeout.sh $ ./read_timeout.sh

If we do not enter any value at the read prompt, after 5 seconds we should see the following message.

Output:

Please enter with in 5 seconds