Install Yosemite by USB

If you experience a hard drive failure and need to re-install the Mac OS X operating system, you can create a USB install media.

You need a working Mac and a minimum of an 8GB USB pen drive.

  1. On a working Mac running Yosemite go to the AppStore and download Yosemite.
  2. Plug in the USB and format it using Mac OS X (Journaled) with a GUID partition scheme – leave the name as Untitled
  3. Open ‘Terminal’
  4. Use the following command
sudo /Applications/Install OS X Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install OS X Yosemite.app --nointeraction

It takes a good 20 minutes to complete and once finished, in the  ‘Terminal’ app, you will see the line

Copy complete.
Done.

Put the USB drive into the Mac you want to install on and when it boots hold down the alt key and choose your USB drive.

Open an Application from the command line

If you regularly use the command line and want to directly open an application and pass a file to it you can use the following:

open -a TextEdit ~/Documents/myfile.txt

The switch -a says use this application:

More switches from the command line:

open --help 
-a Opens with the specified application.
-b Opens with the specified application bundle identifier. 
-e Opens with TextEdit.
-t Opens with default text editor.
-f Reads input from standard input and opens with TextEdit.
-F --fresh Launches the app fresh, that is, without restoring windows. Saved persistent state is lost, excluding Untitled documents.
-R, --reveal Selects in the Finder instead of opening.
-W, --wait-apps Blocks until the used applications are closed (even if they were already running).
-n, --new Open a new instance of the application even if one is already running.
-j, --hide Launches the app hidden.
-g, --background Does not bring the application to the foreground.
-h, --header Searches header file locations for headers matching the given filenames, and opens them.
--args All remaining arguments are passed in argv to the application's main() function instead of opened.