Shell Script Help - Automatically assign users to group

Question

Recently, I have just started to learn linux and I am currently trying to make a shell script that can automate the task of creating user accounts, assigning them passwords and then assigning them to groups.

I have got so far as being able to create the user account and creating a random password for them by using file descriptors, but have no idea of how I can automatically assign them to a group.

If it matters I am using the Raspberry Pi.

The code I have so far is:

exec 3< users.txt
exec 4< passwords.txt

while read iuser <&3 && read ipasswd <&4 ; do
    adduser $iuser
    echo $ipasswd | passwd --stdin $iuser
done

Answer 1

Based on comments - you probably want to read the manpage for adduser.

In particular :

-G, --groups GROUP1[,GROUP2,...[,GROUPN]]] A list of supplementary groups which the user is also a member of. Each group is separated from the next by a comma, with no intervening whitespace. The groups are subject to the same restrictions as the group given with the -g option. The default is for the user to belong only to the initial group.

So in your script you can:

DEFAULT_GROUP=users
exec 3< users.txt
exec 4< passwords.txt

while read iuser <&3 && read ipasswd <&4 ; do
    adduser -G $DEFAULT_GROUP $iuser
    echo $ipasswd | passwd --stdin $iuser
done