Check Whether a User Exists

Question

I want to create a script to check whether a user exists. I am using the logic below:

# getent passwd test > /dev/null 2&>1
# echo $?
0
# getent pa         


        

Answer 1

Using sed:

username="alice"
if [ `sed -n "/^$username/p" /etc/passwd` ]
then
    echo "User [$username] already exists"
else
    echo "User [$username] doesn't exist"
fi