Macintosh Terminal Pocket Guide

Name

dscl — stdin  stdout  - file  -- opt  --help  --version

Synopsis

dscl [arguments]

The dscl command has many uses, but for our purposes, it’s for creating, modifying, and deleting users. Normally you create users with System Preferences, under Users & Groups (Lion) or Accounts (earlier versions of OS X), and frankly this is the easiest method for a single user. But if you need to do it via the shell (say, for creating multiple users in bulk), dscl is the approved technique. In this section, we’ll create a user on the local Macintosh. First we need to choose:

• A username. We’ll use zippy.

• A password.

• A unique positive integer for the user ID. We’ll use 550.

• A default group for the user to belong to. We’ll use the staff group, whose group ID is 20.

There is no single command to create a user with all necessary attributes; you must issue multiple dscl commands to get the job done. First, we’ll create the user:^[22]

➜ sudo dscl localhost -create /Local/Default/Users/zippy

Immediately set a password so intruders cannot log in:

➜ sudo passwd zippy
Password: *******

Now specify the user ID, a positive integer that must be unique, i.e., no other users on your Macintosh have the same ID. You can discover the highest user ID in use by running:

➜ dscl . list /users UniqueID | awk '{print $2}' \
  | sort -n | tail -1
214

which lists all users and their IDs, extracts the second item (the IDs), sorts them numerically, and then prints the last (highest) ID. Choose a new ID higher than 500, since users with ...