Booting process

  1. The bootloader loads the kernel stored in /mach_kernel. Tip: Use rEFIt as a bootloader for dual booting into GNU/Linux.
  2. Kernel launches the launchd process which is equivalent of init in GNU/Linux.
  3. launchd loads startup processes from several directories (/System/Library/LaunchAgents, /System/Library/LaunchDeamons, /Library/LaunchAgents, /Library/LaunchAgents and corresponding files in ~/Library directory)

Directory structure

  1. /Applications – Holds actual applications. Applications are directories with “.app” extension and contain Mach-O executable and other helper files.
  2. /Library –  Similar to /etc on GNU/Linux. It contains system wide config primarily for applications under /Applications. User-specific settings end up in /Users/<username>/Applications dir.
  3. /Network – contains network mounts.
  4. /System – seems to contain system specific data which is not modified regularly
  5. /Users – Equivalent of /home on GNU/Linux
  6. /bin  – Same as GNU/Linux
  7. /sbin – Same as GNU/Linux
  8. /private – /private/tmp is same as /tmp on GNU/Linux. /private/var is same as /var on GNU/Linux. /private/etc seems to contain settings just like /etc on GNU/Linux.


  1. The correct pronunciation is “Oh-es-ten” and not “Oh-es-X”.
  2. Press “D” while booting up to enable diagnostic checks on the system.
  3. Mouseless copy in iTerm2 [source]
  4. Cheatsheet – A helper app that enables you to do a Long press of command button in any app to reveal all app shortcuts. It only works with Cocoa-based apps, and most apps are Cocoa-based.
  5. Fluid – An app that converts a web page into a Mac app.
  6. Mounting a disk image
    Note: The process is a bit more involved with encrypted images.

    $ hdiutil mount image.iso
  7. To read binary plist files use plutil
    $ sudo plutil -p /private/var/db/dslocal/nodes/Default/users/root.plist
  8. To set/get the hostname from command-line
    $ scutil --get HostName
    $ scutil --set HostName NewHostName

Further readings