Write a shell program to convert all lowercase letter in a file to uppercase letter

QUE: Write a shell program to convert all lowercase letter in a file to uppercase
letter.

ANS -

clear
        echo "Menu"
        echo "1. Lower Case to Upper Case"
        echo "2. Upper Case to lower Case"
        echo "3. Quit"
        echo "Enter ur Choice \c"
        read Choice
        case"$Choice"in
           1] echo "Enter File: \c"
              read f1
              if [ -f $f1 ]
          then
               echo "Converting Lower Case to Upper Case "
                 tr '[a-z]''[A-Z]' <$f1
                             
              else
                     echo "$f1 does not exist"
              fi
              ;;
          2] echo "Enter the File :\c"
             read f1
             if [ -f $f1 ]
             then      
               echo "Converting Upper case to Lower Case to "
             tr '[A-Z]''[a-z]' <$f1
                          
             else 
                  echo "$f1 file does not exist "
             fi
             ;;
         3|*) 
             echo "Exit......."
             exit;;
        esac

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output:

    $ cat >hello
    how r u ....
    how is the day....
    go.
    $ SH36
    Menu
    1. Lower to Upper
    2. Upper to lower
    3. Quit
    Enter ur Choice 1
    Enter the File :HELLO
    Converting Lower case to Upper Case to
    HOW R U ....
    HOW IS THE DAY.
    GO   
    $ SH36
    Menu
    1. Lower to Upper
    2. Upper to lower
    3. Quit
    Enter ur Choice 1
    Enter the File :HELLO
    Converting Lower Case to Upper Case
    XCO
    ASA
    GATE