case statement

1. let's create a directory and some files for this example

   $ cd
   $ mkdir caserdir
   $ cd  casedir
   $ touch hello.text hello2.text
   

2. Here are the contents of the script called case.sh:

   #!/usr/bin/sh
   
   x=$1
   echo "argument was $1"
   case $x in
   
   a) echo "got a" ;;
   b) echo "got b" ;;
   *) echo "what ??" ;;
   
   esac
   
   

3. run this script three times and each time use a different argument a, b and then c.

4. now let's write a for loop on the command line and give it different arguments

   $ for x in *
   > do
   > sh case.sh $x
   > done
   

5. now let's create some files in this directory

   $ touch a b c d e f
   $ touch aa ab ac bb cc
   

6. re-run the for loop on the command line again
7. edit the script by adding one line to the case statement:

   #!/usr/bin/sh
   
   x=$1
   echo "argument was $1"
   case $x in
   
   a) echo "got a" ;;
   b) echo "got b" ;;
   ??) echo " got two characters" ;;
   *) echo "what ??" ;;
   
   esac
   

8. re-run the for loop on the command line again
9. edit the script by adding one line to the case statement:

   #!/usr/bin/sh
   
   x=$1
   echo "argument was $1"
   case $x in
   
   a) echo "got a" ;;
   b) echo "got b" ;;
   a?) echo " got two characters starts with a" ;;
   ??) echo " got two characters" ;;
   *) echo "what ??" ;;
   
   esac
   

10. re-run the for loop on the command line again
11. edit the script by adding one line to the case statement:

    #!/usr/bin/sh
    
    x=$1
    echo "argument was $1"
    case $x in
    
    a) echo "got a" ;;
    b) echo "got b" ;;
    a?) echo " got two characters starts with a" ;;
    ??) echo " got two characters" ;;
    b?) echo " got two characters starts with b" ;;
    *) echo "what ??" ;;
    
    esac
    

12. re-run the for loop on the command line again
13. did you get what you expected??? how would you fix this?