Question – How to add [Y/n] confirmation in our own shell scripts?
Many times you have seen commands ask for confirmation [Y/n] or [Yes/No] input. This is a very useful part to know if a user wants to proceed with remaining steps for not. You can also add the same function to your script. This article will help you with examples of (Bash Script – Prompt to Confirm (Y/N, YES/NO)) this type of inputs.
#1. Bash (Yes/No) Prompt
This example code will prompt for confirming once if you give wrong input, the program will exit with status 1. The below example code will accept only Y or n or yes or no (Not case-sensitive).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | #!/bin/bash read -r -p "Are You Sure? [Y/n] " input case $input in [yY][eE][sS]|[yY]) echo "Yes" ;; [nN][oO]|[nN]) echo "No" ;; *) echo "Invalid input..." exit 1 ;; esac |
#2 Prompt for Confirmation (in Loop)
This is another example code will prompt for confirmation until you give proper input like (Y, N, YES or NO). If you give wrong input, it will again prompt for correct input and repeat the same steps. This example will accept only Y or N or YES or NO (Not case-sensitive).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | #!/bin/bash while true do read -r -p "Are You Sure? [Y/n] " input case $input in [yY][eE][sS]|[yY]) echo "Yes" ;; [nN][oO]|[nN]) echo "No" ;; *) echo "Invalid input..." ;; esac done |
In the 2nd example. loops goes on infinity even if user type yes or no.
use break statement to terminate the loop upon valid input.
while true
do
read -r -p “Are You Sure? [Y/n] ” input
case $input in
[yY][eE][sS]|[yY])
echo “Yes”
break
;;
[nN][oO]|[nN])
echo “No”
break
;;
*)
echo “Invalid input…”
;;
esac
done
It goes to infite loop. didn’t ask for user input !
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
test.ksh[4]: read: no query process
Thanks for your page, but there is a bug here –
This – is incorrect. You need to drop the semicolon at the end of the line ‘while true;’
while true:
do
This is correct –
while true
do
Thanks Jeff,
The article has been updated.