Overview of Unix Switch Case Statements:
In this tutorial, we will see how a switch case block can be used when creating conditional flow depending on the various values of a single expression.
Unix Shell The case-esac Statement
Unix Video #16:
The Shell Switch Case Syntax and Examples:
case <word> in <first pattern>) <statements> ;; <second pattern>) <statements> ;; *) <default statements> ;; esac
Here, the value of the word expression is matched against each of the choice patterns. If a match is found then the corresponding statements are executed until the ‘;;’ statement is encountered. If there is no match, the default statements under ‘*)’ are executed.
The following is an Example of a switch case program:
echo “Enter a number” read num case $num in [0-9]) echo “you have entered a single digit number” ;; [1-9][1-9]) echo “you have entered a two-digit number” ;; [1-9][1-9][1-9]) echo “you have entered a three-digit number” ;; *) echo “your entry does not match any of the conditions” ;; Esac
To know more about working with loops in Unix, check our upcoming tutorial.