#93 List NetInfo Users

To begin seeing how to work with NetInfo, here's a straightforward script that allows you to easily interface with the NetInfo database through the nireport utility.

The Code

#!/bin/sh

# listmacusers - Simple script to list users in the Mac OS X NetInfo database.
#   Note that Mac OS X also has an /etc/passwd file, but that's
#   used only during the initial stages of boot time and for
#   recovery bootups. Otherwise, all data is in the NetInfo db.

fields=""

while getopts "Aahnprsu" opt ; do
  case $opt in
    A ) fields="uid passwd name realname home shell"    ;;
    a ) fields="uid name realname home shell"           ;;
    h ) fields="$fields home"                           ;;
    n ) fields="$fields name"                           ;;
    p ) fields="$fields passwd"                         ;;
    r ) fields="$fields realname"                       ;;
    s ) fields="$fields shell"                          ;;
    u ) fields="$fields uid"                            ;;
    ? ) cat << EOF >&2
Usage: $0 [A|a|hnprsu]
Where:
   -A    output all known NetInfo user fields
   -a    output only the interesting user fields
   -h    show home directories of accounts
   -n    show account names
   -p    passwd (encrypted)
   -r    show realname/fullname values
   -s    show login shell
   -u    uid
EOF
exit 1
  esac
done

exec nireport . /users ${fields:=uid name realname home shell}

How It Works

Almost this entire script is involved in building the variable fields, which starts out blank. The nireport utility allows you to specify the names of the fields you'd like to see, and so, for example, if the user specifies -a for all interesting fields, nireport actually is fed

fields="uid name realname home shell"

This is a clear, straightforward script that should be quite easily understood.

Running the Script

The listmacusers script accepts quite a few different command arguments, as shown in the usage message. You can specify exact fields and field order by using hnprsu, or you can list all fields except the encrypted password field with -a or force everything to be listed with -A. Without any arguments, the default behavior is to show all interesting user fields (-a).

The Results

First off, let's specify that we want to see the user ID, login name, real name, and login shell for every account in the NetInfo database:

$ listmacusers -u -n -r -s
-2      nobody  Unprivileged User       /dev/null
0       root    System Administrator    /bin/tcsh
1       daemon  System Services /dev/null
99      unknown Unknown User    /dev/null
25      smmsp   Sendmail User   /dev/null
70      www     World Wide Web Server   /dev/null
74      mysql   MySQL Server    /dev/null
75      sshd    sshd Privilege separation       /dev/null
505     test3   Mr. Test Three  /bin/tcsh
501     taylor  Dave Taylor     /bin/bash
502     badguy  Test Account    /bin/tcsh
503     test            /bin/tcsh
506     tintin  Tintin, Boy Reporter    /bin/tcsh
507     gary    Gary Gary       /bin/bash

Notice that it shows many of the administrative accounts (basically everything with a login shell of /dev/null). If we want to see only login accounts, we'll want to screen out the /dev/null shells:

$ listmacusers -u -n -r -s | grep -v /dev/null
0      root    System Administrator    /bin/tcsh
505    test3   Mr. Test Three  /bin/tcsh
501    taylor  Dave Taylor     /bin/bash
502    badguy  Test Account    /bin/tcsh
503    test            /bin/tcsh
506    tintin  Tintin, Boy Reporter    /bin/tcsh
507    gary    Gary Gary       /bin/bash

The badguy account isn't supposed to be there! To find out what's going on there, and to modify NetInfo entries, it's wise to use the Apple-supplied NetInfo Manager application, which can be found in Applications/Utilities or launched from the command line with the command

open -a "NetInfo Manager"