Shell Scripting Tutorial: Shell Script reading from user input and passing arguments to bash script.

To read an input from the user, use the “read” command.

The read command will take the input from the user and assigns to a variable.

Syntax: read <variable_name> example: read website_name

read -p option:

If you want to display a help text to the user, then use “-p” option.

Example 1:

read -p “Enter user name” <variable_name>

read -s option:

When the user enters a value, that value will be displayed in the terminal. To do a silent read, we use “-s” option. This is generally used when we are reading a password value.

Example 2:

I have created a shell script with below program.

#!/bin/bash

read -p “Enter user name  = ” user_name

read -s -p “Enter password = ” password

echo -e “\n\n\nYou have entered ” #use -e to accept escape sequence

echo “user name = $user_name”

echo “Password is = $password”

Output:

As shown above, while entering user name, the input is displayed. But while entering the password, the value is not displayed, because we have used “-s” option.

Example 3:
If you want to store multiple variables inside an array, use “-a” option in read function. “-a” option will instruct shell to read an array. Then while printing the value, display one by one by using the index value.

#!/bin/bash
echo “Enter multiple items”
read -a items

echo “Items : ${items[0]} ${items[1]} ${items[2]} ${items[3]} ”

Output:
Enter multiple items
pro developer tutorial
Names : pro developer tutorial

Example 4:
If you don’t give any variable name while using read command, then if any input provided by the user will go to a special variable called as “REPLY”.

#!/bin/bash
echo “Enter website name”
read
echo “The website name is $REPLY”

Output:
Enter website name
prodevelopertutorial.com
The website name is prodevelopertutorial.com