Hello.
For Knoppix and Kanotix, I can get my wifi up and running with these commands, done as root:

iwconfig
iwconfig ath0 essid MY_ESSID key MY_UMPTEEN_DIGIT_HEX_KEY
pump -i ath0

And the wireless comes on fine.

When I have tried a handful of other distros as a live CD, SimplyMEPIS as but one example, the system offers no complaint about:

iwconfig ath0 essid MY_ESSID key MY_UMPTEEN_DIGIT_HEX_KEY

but on these other distros, they don't recognize:

pump -i ath0

... and the wireless just never works.

Q: If a distro has the appropriate wifi drivers, what text-based commands should be the totality of what is needed? Do other distros have an equivalent of pump that does the job? Or if it isn't on at this point, is there a problem with the wifi setting of the distro?

[I won't preclude the possiblity that I have a buggy box, but I'm intrigued that some distros do in fact work well with it.]

Debian etch and sarge,

So if a distro, perhaps even a non-Debian one, were to accept the iwconfig command without choking, but then not have a command for pump or ifup, then:

can I say the distro is buggy?

No, that's not buggy.

Different distros take different approaches. Fedora & SuSE use ifup which is a script rather than a command. In Slackware, I get an IP address by starting the dhcp daemon with dhcpcd eth0. Some use dhclient. Debian-based distros use pump.

The differences between distributions are sometimes major - System V vs. BSD style system initialization - sometimes minor. Understanding those differences is all part of the fun.