Free Up Inactive Memory in Mac OS X System with Purge Command

Mac OS X has fairly good memory management but it’s not perfect, and sometimes RAM can be held unnecessarily in the “inactive” state despite the contents no longer being needed. If you’ve been participating in memory heavy activities or you just need to free up some available RAM you can actually force Mac OS X to clear out inactive memory.



Launch Terminal, found in /Applications/Utilities/ and enter the following command


Give OS X a minute or two to complete the process

Open Activity Monitor to see the before and after results yourself, you’ll find dramatic changes at the “Free”, “Used”, and “Inactive” meters under System Memory.

The purge command forces disk and memory caches to be emptied, offering a ‘cold disk buffer cache’ which is similar to the state of the operating system after a reboot. Of course, the benefit of using purge rather than rebooting is that you don’t have to restart the machine and you can maintain currently active applications while still freeing up memory


Mac OS X Lion 10.7 : Xcode 4.1 for Lion is free on the App Store

Xcode provides everything developers need to create great applications for Mac, iPhone, and iPad. Xcode 4 has been streamlined to help you write better apps. It has unified user interface design, coding, testing, and debugging all within a single window. The Xcode IDE analyzes the details of your project to identify mistakes in both syntax and logic, it can even help fix your code for you.

Xcode 4.1 runs on OS X Lion and includes the Xcode IDE, Instruments, iOS Simulator, the latest Mac OS X and iOS SDKs, and hundreds of powerful features:

Innovative tools to help you create great apps
– Interface Builder is fully integrated as a design canvas within the Xcode IDE
– The Assistant shows files related to what you’re editing, such as the header, superclass, or controller
– The Version editor shows a live source code comparison through Git or Subversion history
– Live Issues display errors as you type, and Fix-it can correct the mistakes for you
– Apple LLVM compiler now includes full support for C++, in addition to C and Objective-C
– The new LLDB debugging engine is faster and more memory-efficient than GDB
– Instruments adds System Trace and new iOS instruments including OpenGL ES

mac lion xcode 4.1 free

mac lion xcode 4.1 free

Streamlined interface that is faster and easier to use
– Design your interface side by side with the backing source code
– Create connections from your GUI design directly to the related source code
– Use tabs to organize your workspace, or double-click to open files in a new window
– Schemes let you customize exactly how your app will build, run, profile, and deploy
– Debugging and console views slide in without disturbing your place in the editor

mac lion xcode 4.1 free

mac lion xcode 4.1 free

Professional editor keeps you focused on your code
– Click the Jump Bar at the top of the editor to instantly go to another file
– View message bubbles to see errors, warnings, and other issues right beside the code
– Use the ribbon on the left of the editor to fold your code, or highlight scope

mac lion xcode 4.1 free

mac lion xcode 4.1 free

Embedded Apple LLVM technology finds and fixes bugs for you
– Analyzer travels countless code paths looking for logical errors before they become bugs
– Live Issues underlines coding mistakes as you type with no need to build first
– Fix-it can confidently correct mistakes for you with just a keystroke
– Code completion for C, C++, and Objective-C is incredibly fast and accurate

Instruments for visual performance analysis
– Compare CPU, disk, memory, and OpenGL performance as graphical tracks over time
– Identify performance bottlenecks then dive deep into the code to uncover the cause
– Monitor your app directly, or sample the entire system, with very little overhead

mac lion xcode 4.1 free

Mac lion xcode 4.1 free

To test or deploy applications on an iOS device you must be a member of Apple’s iOS Developer Program. To submit your Mac or iOS apps to the App Store you must be a member of the Mac or iOS Developer Program. Some features may require Internet access.

What’s new in Xcode 4.1 for OS X Lion
– Includes SDKs for OS X Lion and iOS 4.3
– Interface Builder support for Auto Layout and new Aqua controls such as NSPopover
– Full screen support in workspace, project, and organizer windows
– Project modernization to identify and resolve out of date build settings
– Behaviors can be customized and assigned to unique key bindings
– Source control enhancements to pushing, pulling, and management of remote servers
– Assistant editor support for display of generated assembly and preprocessed output
– Additional bug fixes and stability improvements

MAC OS X – Keyboard Shortcut – How to Force Quit an Application in Mac OS

Step #1: Press Command – Option – Escape simultaneously. If you need more explanation on how to find these keys read on:

  1. Command is the button with the curly clover pattern on it. In pre 2008 apple keyboards it also had an apple icon on it. It is in the bottom left of your keyboard.
  2. Alt/Option key is located at the bottom left of your keyboard.
  3. Escape (Esc) is located at the top left hand corner of your keyboard.

Step #2: Select the application you want to force quit from the “Force Quit Applications” window that pops up. If the program has crashed, it will typically say “not responding” next to it in this menu.

Step #3: Click the button that says “Force Quit”.

In Dock – Make Hidden Applications Icons Transparent

If you hide a lot of applications you can make there icons transparent in the dock. A very good visual clue.


defaults write showhidden -bool YES
killall Dock


defaults write showhidden -bool FALSE
killall Dock

Mac OS X – Taking Screenshots

KeyBoard Shortcuts

  • Command-Shift-3: Take a screenshot of the screen, and save it as a file on the desktop
  • Command-Shift-4, then select an area: Take a screenshot of an area and save it as a file on the desktop
  • Command-Shift-4, then space, then click a window: Take a screenshot of a window and save it as a file on the desktop
  • Command-Control-Shift-3: Take a screenshot of the screen, and save it to the clipboard
  • Command-Control-Shift-4, then select an area: Take a screenshot of an area and save it to the clipboard
  • Command-Control-Shift-4, then space, then click a window: Take a screenshot of a window and save it to the clipboard

In Leopard and later, the following keys can be held down while selecting an area (via Command-Shift-4 or Command-Control-Shift-4):

  • Space, to lock the size of the selected region and instead move it when the mouse moves
  • Shift, to resize only one edge of the selected region
  • Option, to resize the selected region with its center as the anchor point

Set Default Formats

defaults write type image_format
killall SystemUIServer

Where image_format is one of jpg, tiff, pdf, png, bmp or pict

From the Terminal

The screencapture command in the Terminal can also be used to capture screenshots, and is useful for scripts. Here is an example.

screencapture -iW ~/Desktop/screen.jpg

Mac OS X Lion Security Enhancements – Improved ASLR

On July 20, Apple released Mac OS X Lion which, despite a million downloads in the first 24 hours, has been met with mixed reactions from early adopters. Despite the tepid enthusiasm, there are some important security enhancements to be gained in the upgrade.

  • Improved ASLR – Address Space Layout Randomization (ASLR) is now fully implemented in Mac OS X Lion, making it more difficult for attackers to render buffer exploits such as heap sprays and stack based attacks.
  • FileVault 2 – Encrypts the entire drive using 128-bit XTS-AES; recovery password can be stored with Apple if desired; Instant wipe immediately removes the encryption key (rendering the drive contents inaccessible), then wipes the entire drive. Additionally, File Vault 2 is now compatible with removable media and Time Machine backups.
  • Safari – In Lion Safari, Webkit runs as a separate sandboxed process, further hardening against remote attacks.
  • As an additional security boost – Apple’s Mac OS X Lion does not preinstall Java or Flash.

the security features have attracted a positive response from security experts. Dino Dai Zovi from consultancy trail of Bits told the Register: “It’s a significant improvement, and the best way that I’ve described the level of security in Lion is that it’s Windows 7, plus, plus. I generally tell Mac users that if they care about security, they should upgrade to Lion sooner rather than later, and the same goes for Windows users, too.”

From a security standpoint, none of these enhancements are enough to compel me to upgrade (for starters, I never use Safari and have already uninstalled Java and Flash) But if you’re planning to upgrade for other reasons, the Lion security enhancements are certainly nice bennies.