macOS

SIP(System Integrity Protection) is enabled by default since El Capitan

$ csrutil status
System Integrity Protection status: enabled.

How to Delete Software on macOS

Unlike Windows, there's no Registry in macOS, so programs can be directly deleted.

• /Applications: software programs, apps can be directly deleted from here
• /Library and ~/Library: user preferences and resources

Library

• System Library: /System/Library
• Local Library: /Library
• User Library: ~/Library

Wired memory

Critical information stored in RAM by the system, its kernel, and some key application components. This stuff is basically frozen – it allocates its space and never moves to the hard drive or gets replaced with user-level data when RAM becomes scarce. An interesting thing to note about wired memory is that it scales based on how much total system memory is installed. For example, a Mac with 1GB of RAM may show 400MB of wired memory, while a Mac with 4GB of RAM may use 700MB. The more memory you have, the more your Mac wants to use it!

Apple Open Directory

https://en.wikipedia.org/wiki/Apple_Open_Directory

Short-cuts

terminal page up or down: fn+up or fn+down

Read NTFS Portable HardDrives

Use Paragon NTFS for Mac

Library

There are 3 Library folders:

• /System/Library
• /Library
• ~/Library

E.g. download JDK/JRE dmg file from here, Java JDK/JRE will be installed in /Library folder: /Library/Java/JavaVirtualMachines/jdk1.7.0_72.jdk

MetaData

$ ps -e | grep md

/System/Library/Frameworks/CoreServices.framework/Frameworks/Metadata.framework/Support/mds

Path in Mac

Xcode Dev Tools

/Applications/Xcode.app/Contents/Developer/usr/bin

Set JAVA_HOME in Mac OS X::

export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home

Load ~/.bash_profile

1. run

$ source ~/.bash_profile

2. or run

$ bash

3. or change default setting to bash:

Terminal->Preferences->Shells open with->change Command to "/bin/bash"

Mac OS X Package manager

Mac homebrew http://mxcl.github.com/homebrew/

Mac OS Commands

lsbom

List the contents of an installer's bom (bill of materials) file. This can be used to find out what files an installer will add/replace in your system before running it. It can also list details of a previous install.

$ lsbom -fls  /private/var/db/receipts/org.macports.MacPorts.bom | (cd /; sudo xargs rm)

Mac OS X empty trash

$ sudo rm -rf ~/.Trash/*

Apple Silicon

Check if your software is ready for Apple silicon: https://isapplesiliconready.com/

Rosetta 2: announced in 2020, to aid in the Mac transition to Apple silicon. The software permits many applications compiled exclusively for execution on x86-64-based processors to be translated for execution on Apple silicon.

Universal 2 binary format: also introduced in 2020, allows applications to run on both Intel x86-64-based and ARM64-based Macintosh computers, to enable the transition to Apple silicon.

(Why 2? 1 was for transition from PowerPC to Intel)