TweetFollow Us on Twitter

Mac In The Shell: Plumbing the Depths

Volume Number: 23 (2007)
Issue Number: 08
Column Tag: Mac In The Shell

Mac In The Shell: Plumbing the Depths

Finding hidden gems in application bundles

by Edward Marczak


With the advent of OS X, most Mac developers were introduced to the concept of bundles. More properly divided into bundles or packages, they both refer to a file-system directory that groups related resources together. This is true for frameworks (bundles: transparent structures that a user can easily access the contents of), applications (a package: an opaque bundle that requires work on the part of the user to open; contents are not easily modified), kernel extensions (another package), certain document types (check out Pages and Keynote, for example) and others. A bundle follows a very specific file layout, meaning, you'll know where to go find the goods. Follow along for a tour, and let's uncover some hidden apps.

Inside a Bundle

Those of us working with the Macintosh for a long enough period of time remember ResEdit, the resource format of OS 9, and all of the types we could store in the resource fork of a file. While OS X recognizes and respects the traditional dual-fork file, its format is deprecated, being replaced by the bundle. The purpose of a bundle is to keep the resources of an application, plug-in or framework in one place. This makes the contents easy to locate and easy to move without damage. What can go into a bundle? Well, technically anything, but you'll typically find the following types of data stored there:



Private libraries

String resources

Executable code

Naturally, it's the latter that interests us in this article.

Typically, to launch an application from a shell, you'd use the open command, like so:

open /Applications/

This will always run the application in the context of the user, even if launched from a root shell, as shown in figure 1:

Figure 1 – TextEdit running as a standard user.

Of course, there are times where you may want (or need) an app to be running with some elevated privileges. How can we achieve this? Time to go digging!

A Direct Launch

As mentioned, a bundle conforms to a specific layout. Listing 1 shows this hierarchy using TextEdit as an example.

Listing 1 – as bundle

The first item in all modern application bundles is the Contents folder. It is under this folder that all other objects reside. Within the Contents folder, you'll find an Info.plist file that tells the Finder many things about this bundle, including the bundle name, version, signature, applicable data types and more. You'll also find a Resources subdirectory, typically containing the images, sounds, movies and other resources used by the application. The application's executable itself resides in the MacOS subdirectory. If you are to look in there now, you'll find the TextEdit application. You can launch the application directly from here.

Gain a root shell using your preferred method, and launch the TextEdit application directly – not using open. Like this:

# /Applications/

Now let's have a look in Activity Monitor, and you'll see that it's running with root privileges.

Figure 2 – TextEdit running with root privileges

Of course, the real point of this is not so much running with root, but the fact that you can access these binaries from the shell in some meaningful way.

Where's the Plunger?

Well, launching TextEdit is nice and all, but, not extremely practical. I'd like to continue with two very real-world examples that have made a difference in my daily work. While every GUI application will have its "true" binary buried in the application package, it may also have any number of helper-apps or other binaries that the app relies on. These are typically found in the Resources directory of the bundle. The easiest way to find executables in a bundle would be, in a shell, to change into the bundle directory and use this handy find command:

find . -type f -perm -100

This will allow you to quickly scour Application and Framework bundles. For instance:

$ cd /System/Library/CoreServices/RemoteManagement/
$ find . -type f -perm -100
./Contents/Support/Remote Desktop Desktop Message

That's some wonderfully revealing information!

Secure Copy

The first really useful binary comes from the MacFUSE project. If you've installed MacFUSE core and the pre-compiled ssh filesystem, run our find command in the bundle. (If you haven't installed this, you should! It's an incredible resource. Find out more at Out of all the things we're returned, this turns out to be what we're looking for:


The sshfs-static binary lets us mount ssh file systems via a shell command rather than using the GUI app to do so. What's this good for? Automation, of course! In fact, you can use it to mount a remote ssh file system proactively, or in response to just about any event.

The easy thing to imagine is a nightly file copy. Mount the file system first, then, use ditto, rsync, or your preferred file moving method, and then unmount (using the standard umount command as, under OS X, there is no FUSE-specific unmounting needed). Better yet, though, think about a launchd job that watches a particular folder and perhaps copies files to a remote location as they show up in a source folder. Hmmmmmmm. So, how can we use this thing?

One way to make your life easier would be to symlink the sshfs-static binary to some appropriate location in your path. I'm going to run it straight from the application package, however, so for these examples, you'll need to change directly into the directory.

First, create a mount point for the file system. Then run the sshfs-static app and supply the following parameters:

-oreconnect,volname=name appearing in the Finder

The "reconnect" option, supplied with the -o switch isn't necessary, but does make things smoother if there's a network interruption and you're disconnected.

Since this all rides on top of ssh, ssh keys are respected. So, if you've generated some password-less keys, just like ssh, you won't be prompted for a password. Let's see this in action. First, I created /tmp/ssh as a mount point. Then, I used sshfs-static to mount a remote system:

$ ./sshfs-static /tmp/ssh -oreconnect,volname=wsweb
kextload: /System/Library/Filesystems/fusefs.fs/Support/fusefs.kext loaded successfully

...and let's take a look at it with mount:

$ mount
/dev/disk0s2 on / (local, journaled)
[snip] on /private/tmp/ssh (nodev, nosuid, synchronous, mounted by marczak)

Figure 3 shows the result of this in my Finder sidebar.

Figure 3: An ssh file system ("wsweb") as seen in the Finder

Very, very, very cool.

Network Probing

While 'black-hat' tools such as nmap sometimes get a bad rap, the fact is that tools like this are also perfect for system administrators when troubleshooting network issues. "Can I reach that port?" and "Is the target port open and responding?" are two of the most frequently asked questions when troubleshooting issues and planning network configurations. While I load nmap on my machine, I often find myself remotely accessing someone in need of assistance because his or her e-mail app "won't work" (residential ISPs typically block port 25) or iChat won't work in some manner (misconfigured/tightly restricted firewalls sometimes will block AIM or Google Talk/Jabber). It would, of course, be a chore and not very friendly to go load nmap and other tools onto someone else's system at that time. Is there a substitute built in to OS X?

Network to the rescue! Huh?!? You expected a shell utility, right? Well, there's one hidden in the very graphical Network that's found in your Utilities folder. Let's run our find command:

$ cd /Applications/Utilities/Network\
$ find . -type f -perm -100
./Contents/MacOS/Network Utility

Of course, we knew about MacOS/Network Utility, but Resources/stroke looks interesting! Nicely enough, the developer that wrote stroke was also kind enough to include a usage statement if you run it without parameters:

$ ./stroke 
2007-06-22 08:41:13.136 stroke[2113] stroke address startPort endPort
Let's see it in action:
./stroke 20 500
Port Scanning host:
         Open TCP Port:         22       pcanywherestat
         Open TCP Port:         25
         Open TCP Port:         53
         Open TCP Port:         80
         Open TCP Port:         106
         Open TCP Port:         110
         Open TCP Port:         119
         Open TCP Port:         139
         Open TCP Port:         143
         Open TCP Port:         311
         Open TCP Port:         389
         Open TCP Port:         427
         Open TCP Port:         443
         Open TCP Port:         445
         Open TCP Port:         465

Well, that's another useful tool that was buried, waiting for discovery. (Bonus points if you recognize the OS that I scanned).


The examples given here really only scratch the surface. There are plenty more hidden gems to be discovered. Take a look in your favorite applications. Dig in and see what you find! You will need to go hunt these utilities and helpers down yourself as they won't be in your shell's path.

Media of the month: Lost Season 1. OK, call me cheesy, but I really dig the show and am surprised at how many people have never given it a chance. Well, Summer is here and it's a great time to rent the DVDs and watch them at your own pace. If you're in the Southern Hemisphere, it's Winter....and what a great time to get under a blanket on the couch, sip some tea and watch a show...especially one that takes place on a tropical island! Enjoy.

WWDC 2007 has come and gone now, and got to reinforce the new concepts in Leopard. I hope everyone who went enjoyed the show, and will start practicing with the new tools and APIs...and have new tools, utilities and techniques ready for when Leopard ships. I've been plumbing the depths of the beta from the show, and have been pleasantly surprised.

Until next month, keep exploring!


Apple, Inc. "Bundle Programming Guide"

Ed Marczak gets dressed in the morning, drinks tea and enjoys breathing. All of this comes in handy in his role as Executive Editor of MacTech Magazine, or when running his consulting company Radiotope. They're also good features when around children. Why?


Community Search:
MacTech Search:

Software Updates via MacUpdate

AirPort Utility 6.3.6 - Set up and manag...
Note: Most recent release available only within OS X 10.11 El Capitan update. Use AirPort Utility to set up and manage your Wi-Fi network and AirPort base stations, including AirPort Express, AirPort... Read more
Quicksilver 1.3.1 - Application launcher...
Quicksilver is a light, fast and free Mac application that gives you the power to control your Mac with keystrokes alone. Quicksilver allows you to find what you need quickly and easily, then act... Read more
Tidy Up (Five Users) 4.1.5 - Find duplic...
Tidy Up is a complete duplicate finder and disk-tidiness utility. With Tidy Up you can search for duplicate files and packages by the owner application, content, type, creator, extension, time... Read more
Mellel 3.4.3 - The word processor of cho...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
Skype - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
Bookends 12.6.0 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Access the power of Bookends directly from Mellel, Nisus Writer Pro, or MS Word (... Read more
Apple iBooks Author 2.4 - Create and pub...
Apple iBooks Author helps you create and publish amazing Multi-Touch books for iPad. Now anyone can create stunning iBooks textbooks, cookbooks, history books, picture books, and more for iPad. All... Read more
Web Snapper 3.3.9 - Capture entire Web p...
Web Snapper lets you capture Web pages exactly as they appear in your browser. You can send them to a file as images or vector-based, multi-page PDFs. It captures the whole Web page - eliminating the... Read more
Tunnelblick 3.6beta10 - GUI for OpenVPN...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
EtreCheck 2.5.1 - For troubleshooting yo...
EtreCheck is a simple little app to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support... Read more

Camel Up (Games)
Camel Up 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: | Read more »
The Martian: Bring Him Home (Games)
The Martian: Bring Him Home 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Based on the best selling novel and critically acclaimed film, THE MARTIAN tells the story of Astronaut Mark... | Read more »
This Week at 148Apps: September 21-30, 2...
Leap Into Fall With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above... | Read more »
Tweetbot 4 for Twitter (Social Networki...
Tweetbot 4 for Twitter 4.0 Device: iOS Universal Category: Social Networking Price: $4.99, Version: 4.0 (iTunes) Description: *** 50% off for a limited time. *** | Read more »
Mori (Games)
Mori 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Stop, rewind and unwind with Mori. Time is always running, take a moment to take control. Mori is an action puzzle game about infinitely... | Read more »
100 Years' War (Games)
100 Years' War 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Tower in the Sky (Games)
Tower in the Sky 0.0.60 Device: iOS Universal Category: Games Price: $1.99, Version: 0.0.60 (iTunes) Description: | Read more »
hocus. (Games)
hocus. 1.0.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0.0 (iTunes) Description: New, polished, mind-bending, minimal puzzle game with dozens of levels and extra-ordinary design Features:- Beautifully crafted... | Read more »
Mos Speedrun 2 (Games)
Mos Speedrun 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Mos is back, in her biggest and most exciting adventure ever! Wall-jump to victory through 30 mysterious, action packed levels... | Read more »
3D Touch could be a game-changer, but it...
Were you one of the lucky/financially secure enough ones to buy a new iPhone 6s or iPhone 6s Plus over the weekend? Yup, me too (I’m not convinced I was either of those two things, but let’s go with lucky for now), so I thought I’d delve into just... | Read more »

Price Scanner via

Apple refurbished iPad Air 2s available for u...
Apple has Certified Refurbished iPad Air 2s available for up to $140 off the price of new models. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB Wi-Fi iPad Air 2... Read more
Save up to $100 on Mac AppleCare Protection P...
Adorama has 3-Year AppleCare Warranties on sale for up to $100 off MSRP including free shipping plus NY & NJ sales tax only: - Mac Laptops 15″ and Above: $249 $100 off MSRP - Mac Laptops 13″ and... Read more
Updated Mac Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
12-inch MacBooks in stock for up to $120 off,...
Adorama has 12″ Retina MacBooks in stock for up to $120 off MSRP including free shipping plus NY & NJ sales tax only. For a limited time, Adorama will include a free Apple USB-C to USB Adapter,... Read more
15-inch 2.2GHz Retina MacBook Pro on sale for... has the 15″ 2.2GHz Retina MacBook Pro on sale for $1799 including free shipping. Their price is $200 off MSRP, and it’s the lowest price available for this model (except for Apple’s $1699... Read more
iPhone 6s and 6s Plus Feature Improved Durabi...
Upgraded components in the new iPhone 6s Plus cost $16 more than the components in the earlier iPhone 6 Plus according to a preliminary estimate from IHS Inc. The bill of materials (BOM) for an... Read more
13-inch Retina MacBook Pros on sale for up to...
Adorama has 13″ Retina MacBook Pros on sale for up to $130 off MSRP. Shipping is free, and Adorama charges sales tax for NY & NJ residents only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1199.99 $... Read more
Apple refurbished 2014 13-inch Retina MacBook...
Apple has Certified Refurbished 2014 13″ 2.6GHz/128GB SSD Retina MacBook Pros available $979, $320 off original MSRP. An Apple one-year warranty is included, and shipping is free: - 13″ 2.6GHz/128GB... Read more
iOS 9 Reflections Ten Days In – The ‘Book Mys...
I’ve never been much of an early adopter by philosophy or temperament, although I did buy the iPad Air 2 I’m typing this column on last fall only about a month after Apple unveiled it. However, my... Read more
Apple refurbished Time Capsules available for...
Apple has certified refurbished Time Capsules available for $120 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $179, $120 off - 3TB... Read more

Jobs Board

Senior Payments Security Manager - *Apple*...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior payments security manager to join the Apple Pay security team. You will Read more
*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
*Apple* Site Security Manager - Apple (Unite...
**Job Summary** The Site Security Manager is a high-profile security position at Apple . The Site Manager is the face of Apple Global Security (GS) and primary point Read more
*Apple* Fulfillment Operations Execution Ana...
**Job Summary** The AMR Apple Fulfillment Operations Team is seeking a talented team player to drive the Apple Online Store (AOS) fulfillment performance to ensure a Read more
*Apple* Distinguished Educator (ADE) Communi...
**Job Summary** Apple is seeking candidates for a new position on the Apple Distinguished Educator (ADE) Program team as ADE Community Support Manager. Join a team Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.