add user bash script

I wrote a bash to add user to the system which takes user name as a command line argument.

the only problem is i want it to check /etc/password to see if the user name already exists and if not, add user. my script is not working...

The problem is apparently with the check = "`cat /etc/passwd | grep $username`"

username="echo $@"
check = "`cat /etc/passwd | grep $username`"
if [ -n "$check" ]; then
echo "The name you have chosen already exist"
fi

The problem with grep an user name in /etc/passwd is that the user name can be
similar to another string.

I would use id command to check the user existence, like :

if id $username > /dev/null 2>&1; then
    echo "The name you have chosen already exist"
    exit 1
fi

Thanks a bunch. that solved the problem.

Good
Also, why not just use :

username=$1

instead of :

username="echo $@"

Originally posted by keefaz The problem with grep an user name in /etc/passwd is that the user name can be similar to another string.

So match the pattern properly:

grep "^$username:" /etc/passwd

And please don't cat a file into a command that accepts a filename argument! You can also redirect to its stdin:

grep "^$username:" </etc/passwd