Bash Case Statement

The bash case statement can be used when you have multiple choices conditions. Using bash case statement, it will be more readable and easier to maintain instead of nested if statements. This tutorial shows you the basics and use of the Bash case statement in shell scripts.

The Bash case statement has a similar concept with the JavaScript or C switch statement. The main difference is that unlike the C switch statement, the Bash case statement doesn’t continue to search for a pattern match once it has found one and executed statements associated with that pattern.

case Statement Syntax#

Below is the basic syntax for the Bash case statement:

case EXPRESSION in

  PATTERN_1)
    STATEMENTS
    ;;

  PATTERN_2)
    STATEMENTS
    ;;

  PATTERN_N)
    STATEMENTS
    ;;

  *)
    STATEMENTS
    ;;
esac

Following are the some key points which need to keep in mind while using bash case statement.

• The case statement starts with the case keyword and ends with the esac keyword.
• To use the multiple patterns separate by the | operator. The ) operator terminates a pattern list.
• A pattern can have special characters.
• A pattern and its associated commands are known as a clause.
• It must terminate the each clause with ;;.
• The commands corresponding to the first pattern that matches the expression will execute.
• Use the wildcard asterisk symbol (*) for the final pattern for the default case. It will always match.
• When there is no pattern matched, it returns status zero. Otherwise, the return status is the exit status of the executed commands.

Case Statement Example#

Below is the example to print the official language of a given country using the case statement in bash script:

#!/bin/bash

echo -n "Enter the name of a country: "
read COUNTRY

echo -n "The official language of $COUNTRY is "

case $COUNTRY in

  Lithuania)
    echo -n "Lithuanian"
    ;;

  Romania | Moldova)
    echo -n "Romanian"
    ;;

  Italy | "San Marino" | Switzerland | "Vatican City")
    echo -n "Italian"
    ;;

  *)
    echo -n "unknown"
    ;;
esac

Save the file and run it from the command line.

bash languages.sh

Once you run the script it will ask you to enter the country name. If you will enter the “Lithuania”, it will match the first pattern, and the echo command in that clause will be executed.

It will display the following output:

Enter the name of a country: Lithuania
The official language of Lithuania is Lithuanian

If the entered country doesn’t match with any other then script will execute the echo command inside the default clause.

Enter the name of a country: India
The official language of India is unknown

Conclusion#

You learned how to use the case statement while writing the bash script.

If you have any question or feedback, please leave a comment below.