Linux check user input error handling - linux

Question

I commented the things I have problem.
and also, is there any other way I can exit my loop without using the exit command?.................
#!/bin/bash
while [ "$done" != "true" ] #this don't work
do
echo "Please enter one of the following options"
echo "1. Move empty files"
echo "2. Check file size"
echo "3. Which file is newer"
echo "4. File check rwx"
echo "5. Exit".
echo -n "Enter Choice: "
read scale # starting from this part for checking if user only inputs numbers 1-5 not working
if ! [[ "$scale" =~ ^[0-6]+$ ]]
then
echo "Invalid Input"
fi #up to this part is not working
read -r answer
case "$answer" in
1) ./move_empty
exit 55
;;
2) ./file_size
exit 0
;;
3) ;;
;;
4)
;;
5) done="true";;
esac
done

Answer 1

There are few things Which should be avoided
while [ "$done" != "true" ] --> while [ $done -ne 1 ] /* -ne is not equal to */
case "$answer" in --> case $answer in
Complete Code
var=0
flag=1
while [ $var -ne 1 ]
do
echo "Please enter one of the following options"
echo "1. Move empty files"
echo "2. Check file size"
echo "3. Which file is newer"
echo "4. File check rwx"
echo "5. Exit".
echo -n "Enter Choice: "
read scale
if [ $scale -gt 0 -a $scale -lt 6 ]
then
echo "valid Input, you can procees for switch "
else
echo "invalid input.. go again & give correct one "
flag=0
fi
if [ $flag -eq 1 ]
then
read -r answer
case $answer in
1) ./move_empty
#exit 55
break
;;
2) ./file_size
#exit 0
break
;;
3)
exit 0
;;
4)
;;
5) done="true";;
esac
fi
done
To come out from loop, without using exit command, use break. Here is the answer from man 1 bash
break [n]
Exit from within a for, while, until, or select loop.
If n is specified, break n levels. n must be ≥ 1. If n
is greater than the number of enclosing loops, all
enclosing loops are exited. The return value is 0
unless n is not greater than or equal to 1.