How to: Add a user from the OS X command line

Create a new entry in the local (/) domain under the category /users.
dscl / -create /Users/toddharris

Create and set the shell property to bash.
dscl / -create /Users/toddharris UserShell /bin/bash

Create and set the user’s full name.
dscl / -create /Users/toddharris RealName "Dr. Todd Harris"

Create and set the user’s ID.
dscl / -create /Users/toddharris UniqueID 503

Create and set the user’s group ID property.
dscl / -create /Users/toddharris PrimaryGroupID 1000

Create and set the user home directory.
dscl / -create /Users/toddharris NFSHomeDirectory /Local/Users/toddharris

Set the password.
dscl / -passwd /Users/toddharris PASSWORD

or

passwd toddharris

If you would like Dr. Harris to be able to perform administrative functions:
dscl / -append /Groups/admin GroupMembership toddharris

Read informations about a group, e.g. “_developer”

dscl localhost -read /Local/Default/Groups/_developer

or shorter

dscl . -read /Groups/_developer

If you want to know the groups your user is a member of

id -Gn

Add the user “gustav” to the group “_developer”

sudo dscl . -append /Groups/_developer GroupMembership gustav