After Jeff's article Gutenprint Updates Printer Drivers without a Lot of Bandwidth, readers suggested a few alternatives. Here's an overview in case you find yourself in a similar situation.
Macworld's Suggestion -- Chris Breen pointed out that when you click the "Check Now" button in System Preferences > Software Update, the system automatically schedules future checks to start at that time. So if you click the button at 11:10pm, future automatic checks will also occur at 11:10pm - assuming the Mac is on and not sleeping. Note that on all current Mac models, the Energy Saver pane in System Preferences includes a Schedule button, where you can configure the Mac to turn itself on or wake up automatically.
The Command Line Answer -- Personally, I'd use Apple's "softwareupdate" command to download Apple's updates, and the standard Unix cron tool to schedule it. Every minute the cron program checks a list of scheduled "cron jobs", and executes any which match the current time - Wikipedia has full details, and Apple has a couple useful manual pages.
"softwareupdate --download --all" will download all outstanding updates, but not install them. This is suitable for running nightly at 11:10pm on a Hughes connection, as the download should be completed by 4am (when HughesNet reactivates bandwidth caps) - if the download fails, the Mac will simply try again the next day.
If you're comfortable with UNIX, you can simply use "crontab -e" (or "EDITOR=nano crontab -e" if you dislike the default vi editor -- personally I use "EDITOR=bbedit"). Then add an entry like this to download any outstanding updates at 11:10pm daily (and skip sending a status email each time):
10 23 * * * /usr/sbin/softwareupdate --download --all >> /dev/null
This produces an email like the following:
Subject: Cron <pepper@mac> /usr/sbin/softwareupdate --download --all
Date: Tue, 5 Jan 2010 00:07:15 -0500 (EST)
From: pepper@mac.local (Cron Daemon)
To: pepper@mac.local
Software Update Tool
Copyright 2002-2007 Apple
Done Digital Camera Raw Compatibility Update
Done.
Packages have been saved to /Users/pepper/Downloads
The update is downloaded to a folder with a '.dist' alias inside it -- simply double-click the '.dist' file to run the updater.
The Manual Option -- Of course, you can also download updates manually from Apple. A TidBITS reader wrote in to suggest downloading required updates from http://support.apple.com/en_US/downloads, either with a browser or a scheduling downloader such as Speed Downloader. This is particularly useful if you're caring for multiple Macs, since one installer can be used on all of them - as compared to Software Update, which downloads each updater independently on each Mac and deletes them all when done. Alternatively, manually downloading updates would make sense if you have a fast connection (perhaps at work) and can easily burn CDs or DVDs for Macs with slow or limited connectivity.