Terminate shell script after three invalid input

Question

Restricting user from trying multiple invalid attempt in shell scripting. I wrote the below script but somehow it's not getting me desire output. I have shared the script and script output both. Kindly help. Here I wanted script to terminate if user tried more than 3 times.

While true
do
echo -n "Enter yes or no"
read opt
case $opt in
yes) break ;;
no) break ;;
*) echo "Invalid input"
while [[ $err -le 3 ]]
do
 If [[ $err -le 3 ]]
then
echo "err: $err"
((err++))
break
else
echo "Max limit crossed"
exit 1
fi
done
;;
esac
done

I recommend you to use `select` instead of a loop. This way you don't have the problem with wrong answers. Have a look at the second option in [this answer](https://stackoverflow.com/a/226724/8344060) — kvantour, Dec 04 '20 at 10:30
Does this answer your question? [How do I prompt for Yes/No/Cancel input in a Linux shell script?](https://stackoverflow.com/questions/226703/how-do-i-prompt-for-yes-no-cancel-input-in-a-linux-shell-script) — kvantour, Dec 04 '20 at 10:30
If you think a answer was helpful mark it as accepted, button below up-dwon voting — Aalexander, Feb 14 '21 at 16:10

Aalexander · Answer 1 · 2020-12-11T07:40:51.943

1

This was a nice question and I had a lot of fun solving it. I have to mention that I'm new to shell programming.

  n=0
  until [ $n -ge 3 ] 
  do 
  read line
    if [ "$line" = "XYZ" ]; then 
        echo "Accepted" 
        break
    else
        n=$[$n+1]
        echo " trying " $n "times "   
    fi;
  done

This article helped me a lot to solve it.

edited Dec 11 '20 at 07:40

answered Dec 04 '20 at 10:40

Aalexander

4,987
3
11
34

Thanks Alex .. this approach is really nice and I got that worked . – Rimo1988 Dec 12 '20 at 05:17
Okay, Perfect :) – Aalexander Dec 12 '20 at 08:10
@Rimo1988 if you think this was helpful, mark it as accepted the button below down-upvoting. – Aalexander Feb 14 '21 at 16:13

score 0 · Answer 2 · answered Dec 04 '20 at 10:37

0

Try:

#!/bin/bash
ANSWER=
max=3
while true; do
     echo "Enter yes or no:"
     read -r ANSWER
     [[ $ANSWER == "yes" || $ANSWER == "no" ]] && break
     echo Invalid Input
     ANSWER=
     ((--max))
     [[ $max -le 0 ]] && { echo "Max limit crossed"; exit 1; }
done

answered Dec 04 '20 at 10:37

Jay

66
6

I found this partially opposite of what Alex suggested above. This also should serve the purpose. Thanks – Rimo1988 Dec 12 '20 at 05:18

Terminate shell script after three invalid input

2 Answers2