OS X handles sudo and su identically to Linux.

sudo is a command that, without any additional options, will run a command as root. For example:

% touch /newfile
touch: /newfile: Permission denied
% ls -l /newfile
ls: /newfile: No such file or directory
% sudo touch /newfile
% ls -l /newfile 
-rw-r--r--  1 root  wheel  0 Apr 27 11:45 /newfile

su on the other hand, will switch the current user to root (again without any extra commands). In the example below, I have to run sudo su, since I don't know the root password for my system:

% whoami
alake
% sudo su
$ whoami
root

The key difference between sudo and su is sudo runs a command as root, whereas su makes you root. Much like other command line utilities there are a number of alternative ways to use both sudo and su, if you're interested you can always run man <command> eg. man sudo to get more information.

ifconfig gives information about all interfaces, including WLAN. The WLAN interface is usually en1.

$ ifconfig en1
en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether 20:c9:d0:97:22:e9 
        inet6 fe80::22c9:d0ff:fe97:22e9%en1 prefixlen 64 scopeid 0x5 
        inet 192.168.1.137 netmask 0xffffff00 broadcast 192.168.1.255
        media: autoselect
        status: active

airport -I gives information about WLAN interfaces (check out the man page for additional options)

$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport -I en1
     agrCtlRSSI: -68
     agrExtRSSI: 0
    agrCtlNoise: -85
    agrExtNoise: 0
          state: running
        op mode: station 
     lastTxRate: 54
        maxRate: 54
lastAssocStatus: 0
    802.11 auth: open
      link auth: wpa2-psk
          BSSID: 11:22:33:44:55:66
           SSID: serenity
            MCS: -1        channel: 6