Change password
passwd
passwd web-lab
List users
cat /etc/passwd
Groups
groups groups root
List all members of a group
grep 'grpup-name-here' /etc/group
Add user to group
usermod -G group user
Remove user from group
gpasswd -d user group
Deny SSH shell access
usermod user -s /bin/false
Allow SSH shell access
usermod user -s /bin/sh
chsh -s /bin/bash user
Adding new users
How To Add, Delete, and Grant Sudo Privileges to Users on a Debian VPS
adduser newuser
ssh newuser@your_server_ip_address
Remove a user in Debian (UNIX)
to remove a user and their home directory, use:
deluser -remove-home <user-name>
to remove all of their files on the server:
deluser -remove-all-files <user-name>