The case statement

The case statement enables to compare a pattern with various other patterns and execute a block of code if a match is found. The shell case statement is associatively powerful than the switch statement in C and the case statement in Pascal or. The motive for such a condition is that it is possible to compare strings in the shell case statement by using wildcard characters.

Syntax

case string1 in

str1)

commands;;

str2)

commands;;

*)

commands;;

esac

Practice 1

The given shell program will create and show and delete a file by using case statement

# vi casefile

echo -e "Enter the filename :\\c"

read fname

echo -e "Enter the selection (1-create;2-display;3-delete):\\c"

read choice

case $choice in

1) cat   >          $fname;;

2) cat $fname;;

3) rm $fname;;

*) echo "Select the option among [1-3] "

break;

esac

# sh casefile

Enter the filename: sivam

Enter the selection (1-create;2-display;3-delete):1

Using case statement this is a demo to create a file

To display the file

^d

# sh casefile

Enter the filename: sivam

Enter the selection (1-create;2-display;3-delete):2

Using case statement this is a demo to create a file

To display the file

# sh casefile

Enter the filename: sivam

Enter the selection (1-create;2-display;3-delete):4

Select the option among [1-3]

The given program gives 3 selections from 1 to 3. It Depending on the value in which is chosen the corresponding command is executed. If any other value is selected, it will show "Select the option among [1-3]".