Shell Programming and Scripting

#!/usr/bin/ksh

script_menu() {
while :
       do
       clear
echo  some action here
read choice
case $choice in

1) 
some action as per choice;;
2)     
       return;;
3)
       exit;;
    esac 
 done
}

#Main Menu
while :
       do
       clear
       echo ----------------------------------------------------
       echo    ******************Main Menu******************
       echo ----------------------------------------------------
       echo Select a Choice
       echo [1] call sub menu
       echo [2] View Log Files
       echo [3] Exit
       echo ----------------------------------------------------
       echo Select choice {1-2}:
read choice
case $choice in
1)
       script_menu;;
2)     
       echo files; 
       echo Enter file name;
       read -r filename ; find "$filename"_*.* -type f ! -name ".*" 2>errorlog 
       echo Press Enter; 
       read x;;
2.1) Can I solve above question here, like this?

3)   
       exit;;
*) 
       echo Invalid Number
     esac
done

read -r filename ; find $filename"_"*.* -type f ! -name ".*" 2>errorlog

$ cat xxx
#!/usr/bin/ksh

#  Set select construct prompts for each menu level.
typeset -r MAINPROMPT="Select a main option: "
typeset -r MANGOPROMPT="Select mango option: "

#  Loop main menu until user exits explicitly.
while :
do
  print "\nTop-level Menu Title Goes Here\n"
  PS3=$MAINPROMPT  # PS3 is the prompt for the select construct.

  select option in "mango (has a sub-menu)" tango rango exit
  do
    case $REPLY in   # REPLY is set by the select construct, and is the number of the selection.
      1) # mango (has a sub-menu)
         #  Loop mango menu until user exits explicitly.
         while :
         do
           print "\nmango sub-menu title\n"
           PS3=$MANGOPROMPT
           select option1 in add substract exit
           do
             case $REPLY in
               1) # add
                  print "\nYou picked [add]"
                  break  #  Breaks out of the select, back to the mango loop.
                  ;;
               2) # subtract
                  print "\nYou picked [subtract]"
                  break  #  Breaks out of the select, back to the mango loop.
                  ;;
               3) # exit
                  break 2  # Breaks out 2 levels, the select loop plus the mango while loop, back to the main loop.
                  ;;
               *) # always allow for the unexpected
                  print "\nUnknown mango operation [${REPLY}]"
                  break
                  ;;
             esac
           done
         done
         break
         ;;
      2) # tango
         ;&  # Fall through to #3
      3) #rango
         print "\nYou picked $option"
         break
         ;;
      4) # exit
         break 2  #  Break out 2 levels, out of the select and the main loop.
         ;;
      *) # Always code for the unexpected.
         print "\nUnknown option [${REPLY}]"
         break
         ;;
    esac
  done
done

exit 0
$