Using while loop to make user input only an existing user

Question

I am trying to make it that if the user inputs a non existing user they would be asked to retry again, but it is the opposite effect. I am sure it is something wrong with my while condition I just cant see :(

code:

#!/bin/bash

echo -n "Name of the username: " 
read username 
while id -u $username >/dev/null 2>&1;
do 
echo "User doesn't exist"
echo -n "Name of the username: "
read username
done

D. Ben Knoble · Accepted Answer · 2020-01-05 21:15:19Z

2

You need to negate the condition with !.

Remember that while cond means execute while cond is true; it is the opposite of until cond (execute until cond is true).

until exists in many languages, including any POSIX-compliant shell; the negation will always work, however.

edited Jan 5, 2020 at 21:15

answered Jan 5, 2020 at 21:11

D. Ben Knoble

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