Shell Programming and Scripting

DIALOG=${DIALOG=dialog}
$DIALOG --title "RFC NUMBER" --clear \
        --inputbox "Please enter an RFC Number" 16 17 2> $rfcfile

retval=$?
rfcval=`cat $rfcfile`

case $retval in
  0)
    echo RFC Number: "$rfcval" >> $accessfile;;
  1)
    exit 1;;
  255)
    rm -rf $accessfile && rm -rf $tempfile && rm -rf $rfcfile && rm -rf $sitefile && exit 1;;
  esac

#!/bin/bash
validinput=0

while [ "$validinput" != "1" ]
do
        echo "Please enter an RFC number"
        read rfcnumber

        case $rfcnumber in
                "")
                        echo Either type in your RFC number, or enter N/A if one is unavailable.
                        ;;
                N/A)
                        echo You have indicated an RFC number is not available.
                        validinput=1
                        ;;
                *)
                        if echo "$rfcnumber" | /bin/grep -E "^[0-9]{5,}$" >/dev/null 2>/dev/null
                        then
                                echo Valid RFC number entered.
                                validinput=1
                        else
                                echo "Invalid RFC number entered"
                                echo "Please enter a minimum of five digits only, or N/A if you don't have one"
                        fi
                        ;;
        esac
done

echo "You provided the following valid input:"
echo $rfcnumber

$ ./script.sh
Please enter an RFC number

Either type in your RFC number, or enter N/A if one is unavailable.
Please enter an RFC number
N/A
You have indicated an RFC number is not available.
You provided the following valid input:
N/A
$ ./script.sh
Please enter an RFC number
123
Invalid RFC number entered
Please enter a minimum of five digits only, or N/A if you don't have one
Please enter an RFC number
ABC
Invalid RFC number entered
Please enter a minimum of five digits only, or N/A if you don't have one
Please enter an RFC number
a12345
Invalid RFC number entered
Please enter a minimum of five digits only, or N/A if you don't have one
Please enter an RFC number
12345a
Invalid RFC number entered
Please enter a minimum of five digits only, or N/A if you don't have one
Please enter an RFC number
1234-567
Invalid RFC number entered
Please enter a minimum of five digits only, or N/A if you don't have one
Please enter an RFC number
123456
Valid RFC number entered.
You provided the following valid input:
123456

trap clear EXIT
DIALOG=${DIALOG=dialog}
while :
do
  rfcval=$($DIALOG --title "RFC NUMBER" --clear \
          --inputbox "Please enter an RFC Number" 16 17 2>&1 >/dev/tty)
  retval=$?
  case $retval in
    0)
      case $rfcval in
        N/A|n/a)
          exit 0 ;;
        [!0-9])
          : ;;
        *[0-9][0-9][0-9][0-9][0-9]*)
          echo "RFC Number: $rfcval" >> $accessfile
          exit 0;;
      esac ;;
    1)
      exit 1;;
    255)
      rm -f "$accessfile" "$tempfile" "$sitefile"
      exit 1 ;;
  esac
done

  case $retval in
    0)
      case $reasonval in
        *^[a-zA-Z0-9_]{15,}$*)
         echo Reason for System Access: $reasonval >> $accessfile
          exit 0 ;;
      esac ;;

trap clear EXIT
DIALOG=${DIALOG=dialog}
while :
do
  rfcval=$($DIALOG --title "RFC NUMBER" --clear \
          --inputbox "Please enter an RFC Number" 16 17 2>&1 >/dev/tty)
  retval=$?
  case $retval in
    0)
      if [[ $rfcval =~ ^[0-9]{5,}$ ]]; then
        echo "RFC Number: $rfcval" >> $accessfile
        break
      elif [[ $rfcval =~ ^(N/A|n/a)$ ]]; then
        break
      fi ;;
    1)
      exit 1;;
    255)
      rm -f "$accessfile" "$tempfile" "$sitefile"
      exit 1 ;;
  esac
done
exit 0