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/$USER/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.

Miscellaneous

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. Enable Mouseless copy in iTerm2

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.

   1 2	$ hdiutil mount image.iso ...

7. To read binary plist files use plutil

   1 2	$ sudo plutil -p /private/var/db/dslocal/nodes/Default/users/root.plist ...

8. To set/get the hostname from command-line

   1 2 3

   $ scutil --get HostName $ scutil --set HostName NewHostName ...

Further readings

1. https://www.matisse.net/OSX/darwin_commands.html
2. https://www.mitchchn.me/2014/os-x-terminal/
3. furbo.org/2014/09/03/the-terminal/
4. https://www.wezm.net/technical/2019/10/useful-command-line-tools/
5. https://www.dyx.name/posts/macunix.html