Option of Read Command:
| Option | Purpose |
|---|---|
| -p | It is used to provide a helping message for the user before the input prompt. |
| -s | It is used to take invisible input from the user. This option is used to take a password or secret data. It is called silent mode. |
| -t | It is used to set time in seconds to wait for taking input from the user. |
| -n | It is used to set the limit of input characters. |
Example-1: Use of read command without variable
The read command can be used without any variable. The $REPLY variable is used to read the input taken from the user by the read command without variable. Create a bash file with the following script to know how to use the read command without any variable.
echo "What is your favorite programming language?"
# Take input without defining variable
read
# Print the input value
echo "Your answer is $REPLY"
Output:
The following output will appear after executing the above script.
Example-2: Using simple read command
Create a bash file with the following script to know how to use the read command with a variable. After running the script, the program will wait for the user input. When the user types the data and press enter, the data will be stored in the answer variable. The value of the answer variable will be printed later.
echo -n "What is your favorite food: "
# Assign input value into a variable
read answer
# Print the value of the variable
echo "Oh! you like $answer!"
Output:
The following output will appear after executing the above script.
Example-3: Using read command with options
Create a bash file with the following script to know how to use both –p and –s options together in the bash script. In this example, the username and password will be taken from the user and compared with the particular value to check the username and password are valid or not.
# Type your Login Information
read -p 'Username: ' user
read -sp 'Password: ' pass
# Check the username and password are valid or not
if (( $user == "admin" && $pass == "12345" ))
then
echo -e "\nSuccessful login"
else
echo -e "\nUnsuccessful login"
fi
Output:
The following output will appear after executing the above script.
Example-4: Using read command to take multiple inputs
The multiple inputs can be taken at a time by using the read command with multiple variable names. In the following example, four inputs will be taken in four variables by using the read command.
# Taking multiple inputs
echo "Type four names of your favorite programming languages"
read lan1 lan2 lan3 lan4
echo "$lan1 is your first choice"
echo "$lan2 is your second choice"
echo "$lan3 is your third choice"
echo "$lan4 is your fourth choice"
Output:
The following output will appear after executing the above script.
Example-5: Using read command with the time limit
Create a bash file with the following script to take time-restricted input from the user. Here, the time will be counted in seconds. In the following example, the program will wait for 5 seconds for the user’s input, and if the user is unable to type the data within 5 seconds, the program will exit without value.
# Take input with time limit
read -t 5 -p "Type your favorite color : " color
# Print the input value
echo $color
Output:
The following output will appear after executing the above script. The input value has been given in the first execution, and in the second execution, no input value has been given within 5 seconds.
Example-6: Use of read command with -n option
Create a bash file with the following script to take input of a specific length. According to the script, the user will be able to enter a maximum of 15 characters as input.
echo "Enter your phone number(Maximum 15 characters):"
# Take input of a maximum 15 characters long
read -n 15 phone
# Add a newline
echo
# Print the input value
echo "Your phone number is $phone"
Output:
The following output will appear after executing the above script.
Example-7: Checking a taken path is file or directory
Create a bash file with the following script to take input a path value from the terminal and check the input path is a directory or file.
# Take the path value from the input
read -p "Enter the valid path: " path
# Check the input values is a directory or not
if [ -d $path ]; then
echo "$path is a directory."
# Check the input values is a file or not
elif [ -f "$path" ]; then
echo "$path is a file."
else
echo "Invalid path."
fi
Output:
The following output will appear after executing the above script.
Example-8: Initialize array using the read command
The array variable can be declared and initialized by using the read command. Create a bash file with the following script to know how to create and initialize an array by using the read command. Next, all elements of the array, the first element of the array, the first two elements, and the last element of the array will be printed.
echo "Enter five numeric values for the array with space:"
# Read values for the array
read -a MyArr
# Print all array values
echo ${MyArr[@]}
# Print the first value of the array
echo ${MyArr[0]}
# Print the first two values of the array
echo ${MyArr[@]:0:2}
# Print the last value of the array
echo ${MyArr[4]}
Output:
The following output will appear after executing the above script.
Conclusion:
Different uses of the read command have been shown in this tutorial by using multiple examples for helping the bash users to know the uses of this command properly and apply it to their script.
