Cool Clever Stuff with CLIX

Two technologies endemic to every Apple/Unix OS X machine that should never incur an add-on expense are access to search engines and other online resources through the Cocoa Services menu and command line operations. This article discusses using the latter for fun and profit.

The Command Line Interface for OS X

If you don't have CLIX on your box yet, you'd best wander over. Click the icon to the right and get the download. It's under 50 KB and it's free. It will be easier to follow this discussion if you're running CLIX.

CLIX is a 'command line interface for OS X'. In a day when Bill Gates makes a big deal out of hiding the command line, Apple bring it back - and it's no mediocre command line either: it's an interface with the very powerful Unix 'shells'.

OS X boxes have 900+ Unix command line programs; all you have to do is access and get acquainted with them. There are things for system maintenance, for network management, and for fun. A bit of everything.

And whilst CLIX is a good way for Unix beginners to get to know Unix and test command line stuff, it's great for the professional too - it saves typing!

For it's one thing to 'know how' to write a complicated command line, consult manpages, figure out the syntax all over again - and it's quite another to have all your command lines stored conveniently in a CLIX file - scroll through, choose, run: it's that simple.

It's a time saver!

CLIX Categories

To make navigation through the extensive CLIX database easier, commands are divided up into a number of categories.

• .Global - global system preferences.
• Address Book - preferences for Apple's Address Book application.
• Calendar - access to Unix calendar data.
• Clean - generic system maintenance operations.
• Dashboard - turning it on, off; getting it to behave.
• Developer - arcane programming stuff.
• Dict - access to Unix dictionary data.
• Disk - generic disk maintenance operations.
• Disk Copy - preferences for Apple's Disk Copy application.
• Dock - preferences for Apple's Dock application.
• DVD Player - preferences for Apple's DVD Player application.
• Finder - preferences for Apple's Finder application.
• List - access to innumerable lists, Unix, Apple, and otherwise.
• Log - access to generic log files.
• Lproj - manage your language project files.
• Misc - access to Unix 'misc' data.
• Network - generic network maintenance operations.
• Purge - generic system maintenance operations.
• Quartz - showing OS X drawing in 'debug' mode.
• Safari - preferences for Apple's Safari application.
• Security - generic security audit and maintenance operations.
• Spotlight - turning it on, off; getting it to behave.
• System - generic system maintenance operations.
• Trash - operations for interfacing with the 'Trash'.

Naturally these categories are somewhat arbitrary; the idea is you will find new (and better) ways to categorise the commands on your own - or add others with new commands. But this discussion will concentrate on the commands categories 'out of the box'.

The 'Big Four'

Most of the Unix commands come from four standard Unix directories.

• /bin. Original repository for 'binary' files (programs).
• /usr/bin. An addition in the classic 'user' mount area.
• /sbin. Contains system (administration) programs.
• /usr/sbin. Additional system (administration) programs.

If you don't have these directories on disk, check with your installer and opt for the 'BSD subsystem'.

Darwin Open Source

The core of OS X is a variant of FreeBSD which is 'open source'. Apple aren't exactly stupid in making the code so accessible: if you haven't seen the arguments of Eric Raymond in favour of open source and explaining why it's so much better than closed proprietary source, look him up and read.

Security through obscurity never worked anyway, and Apple practice security through a good security model, and large portions of Darwin are legacy code coming down from academia and institutions like Lawrence Livermore. The bottom line? You have a lot of very good code at your disposal - infinitely better, for example, than the crumbs tossed to Windows users.

Integration

OS X is a tightly integrated system with both the solid Unix core and the dazzling Cocoa GUI working together. Sometimes your operations will blur out the distinction between the two; your advantage on OS X is that they work so well together.

OK, to the 'fun and profit' part.

.Global

OS X preferences are divided into a number of 'domains'; every user has access to 'global' settings. Many of these are stored in the file:

~/Library/Preferences/.GlobalPreferences.plist

Which, because its name begins with a dot, is normally invisible.

Accessing preferences is normally done with the command line tool 'defaults', a NeXTSTEP addition to FreeBSD found in the Darwin core. Some of the cool clever stuff you can do here:

Address Book

Apple's Address Book application has a hidden debug menu. If it's cool and clever or not is another matter, but it's there.

Calendar

The directory:

/usr/share/calendar

Contains a lot of fun stuff.

The files in this directory are mostly linear databases; the CLIX commands are merely examples of how this data can be used. Remove the 'grep' pipes to see the full output.

Clean & Purge

Two big 'system maintenance' categories. Operations in the 'Clean' category only unlink files when they're to be removed; 'Purge' operations overwrite files before removing them.

These 'cleanup' operations target the following:

.DS_Store, .localized, .MCXLC, Apple Mail, 'recent folders', Project Builder and Xcode, library caches, Calculator, Camino, 'Desktop' files, DVD scripts, file panel prefs, Finder, Full Circle and Talkback, Dock icon caches, launch services caches, library logs, pref panes caches, receipts, Safari, search index (.FBCIndex) files, and /tmp.

Running all these, or combining them in a single shell script, should give you a 'clean machine'.

Developer

Funky stuff for the pro.

Dict

Accesses the oft-overlooked resources in:

/usr/share/dict

The data in this directory is based on 'out of copyright' dictionary and similar resources. Yes, you have spell checking in fourteen languages simultaneously, but you also got these files for the price of your operating system, so use them! Again, remove the 'grep' pipes to see the raw output: the data can be put to many uses!

Disk

Generic disk maintenance.

Many of these commands are obtuse - they're used so seldom it's hard to remember their syntax. And many of them have been incorporated into fancy shareware products with Xmas tree doodads - all you really needed was to remember a command line.

Disk Copy

Apple's Disk Copy application has an 'expert mode'. If it's cool and clever or not is another matter, but it's there.

Dock

Lots of known and not so well known settings. All work with one or more - but not necessarily all - versions of OS X.

Autohide, Launch Animation, Magnification, Mineffect, Orientation, Persistent Apps, Pinning, QuitFinder, Shadow, Show All Files, and Show Hidden.

DVD Player

Apple's DVD Player application has a 'debug mode'. If it's cool and clever or not is another matter, but it's there.

Finder

Lots of known and not so well known settings. All work with one or more - but not necessarily all - versions of OS X.

Animate Info Panes, Animate Window Zoom, Finder Quit, Max Label Lines, Show All Files, and Zoom Rects.

List

Unix has lots of statistics stored all over the place. This is a big category. It also includes 'Aqua' stuff.

Some of these are important to always have at the ready; there are no commands for deleting swap files in your vm directory because that's just a bad idea, despite snake oil salesmen trying to tempt with such a feature (you don't gain anything by it); having any other areas of your hard drive at your fingertips can be crucial.

Log

Log files can be important - and they're all over the place. These commands not only let you see their contents but also clean or purge them.

Misc

Accesses the oft-overlooked resources in:

/usr/share/misc

Again, these are 'database' files. The sample CLIX commands are very useful, but check the raw output by removing the 'grep' pipes.

Network

As the Internet and Unix grew hand in hand, your OS X box is going to have a plethora of heavy duty network management tools.

The 'DHS Threat Advisory' command was added only because some callous soul tried to profit by whipping up paranoia: the 'advisory condition' is a simple (and free) HTTP access.

The 'Ping' example is only one of many ways to check Internet connectivity; Hawkeye represents a more systematic approach. A good way to work this command into something viable is to assemble a list of IPs that are important in your part of the world and poll them at regular intervals. The root servers don't much appreciate your bombarding them either.

Netstat information is of course an excellent way to see what is going in and out of your computer.

Quartz

This category has a single command - but if you haven't got CLIX yet, get it now and try this one - enough said!

Safari

Lots of interesting and very useful stuff, always with more to come. If nothing else at least try the 'debug menu' - very useful things there, such as user agent spoofing (pretending you're a Windows user at IIS sites), checking the data inside Safari's rendering engine, peeking into the memory caches, and more.

Security

One of the most important categories. Remember: security is an 'iterative' process - conduct security audits regularly! At the very least, check your system for empty directories, empty files, compiled file systems, 'world-writables', SGIDs, SUIDs, and your authorization and sudoers files whenever you can.

Why are these audits so important?

• The app_profile directory contains info on who has been doing what on your computer. You might want to remove this data for reasons of privacy, and you might want to check it from time to time to make sure no one has invaded that privacy.

• The authorization and sudoers files tell you who is allowed to do what on your computer. Normally that should only be you. If you are familiar with the contents of these files and if you review them regularly, you will notice if an interloper is keeping you company.

• So-called 'root kits' like to take over a system by compromising the kernel.

• Empty directories and files can be a sign of malfeasance and an attempt to cover it up.

• Set UID files are the most dangerous things on your system. Any files that do not need to be set UID should be altered to remove the threat of malicious privilege escalation.

• World-writable files serve no purpose but to let interlopers compromise you. Performing this audit can't be easier: your system should have no such files at all.

• The 'who' commands show you who is logged onto your system. Normally that should be only you. If it isn't - suspect the worst.

System

Another important - and extensive - category.

If nothing else, try the 'Saver Desktop' command: the way it's set up in CLIX makes it easy to turn on, turn off, and impress your friends all at once!

Trash

This final category has commands for cleaning and purging the contents of the Trash directory. Obviously such commands are applicable to system maintenance scripts.