Managing Users
Create new user
useradd <username>
The -d option can be used to set the home directory for the user. The -m option will force to create the home directory:
useradd -d /home/<username> -m <username>
Change user’s password
passwd <username>
Delete user
deluser <username>
View user’s account info
id <username>
Change ownership of folder/files recursively
chown -R username somedir
Managing Groups
Create new group
groupadd <groupname>
Add an existing User to an existing Group
The -a param means “append” group. Otherwise the new group will overwrite the previous ones.
usermod -a -G <groupname> username
View user’s groups
groups <username>
Add a new user and assign it to an existing group
useradd -G <groupname> <username>
Add user to multiple groups
usermod -a -G group1,group2,group3 <username>
Modify user’s primary group
usermod -g <groupname> <username>
Change folders/files group recursively
chgrp -R <groupname> <folder/file>
Make all new folders/files created inside a directory to inherit the group of such directory
chmod g+s <folder/file>