dotfiles/notes/macos/apple_bsd.md

Apple corner

MacOS is a BSD derivative that constantly does things differently under the hood. While most things are Unix compatible, some things are just different

Basic setup

MacOS requires a few manual interventions to get the system working

# spctl --master-disable

Reveals the option in "Security & Privacy" to run apps from any developer

~/Library/Sounds/madoka_error.aiff

Sound files stored in this directory are available under Sound -> Sound Effects

~/Library/KeyBindings/DefaultKeyBinding.dict

Allows basic remapping for system-wide key binds. Use skhd for complex hotkeys

Basic commands

$ echo 'hello' | pbcopy
$ pbpaste > note.txt

Interact with the system clipboard through terminal. This does not work for images. Install pngpaste for that functionality

$ say 'something'

Says string with system voice. Useful as a notification for when a task is done

$ afplay

Plays the audio of an audio file, such as an mp3 or wav

Disk Utility

$ diskutil list

Lists all the volumes the system currently sees. This works for unmounted and encrypted partitions as well

$ diskutil mount disk1s1

Mounts disk1s1. Most useful to mount USB drives without physically reseeding

$ diskutil apfs unlockVolume disk1s1

Unlocks and mounts an apple file system volume

Launch daemon

Systemd for MacOS. It will automatically load scripts in designated directories on login. It can also be controlled manually through launchctl

$ launchctl load -w ~/Library/LaunchAgents/com.skhd.plist
$ launchctl unload -w ~/Library/LaunchAgents/com.skhd.plist

Loads and starts the skhd daemon. <key>Label</key> must be the same to unload

# launchctl list | grep skhd

Check the status of a running process. First number is the PID, second number is the exit code. If the second number isn't 0 or there's no PID something broke

/Users/emiliko/Library/LaunchAgents/com.launcher.plist

This file will be started automatically on emiliko's login. All paths provided in must be absolute paths from root. Use /Users/emiliko/ not ~/

/Users/emiliko/Library/LaunchAgents/com.launcher.plist
<key>StandardOutPath</key>
<string>/tmp/skhd.out</string>
<key>StandardErrorPath</key>
<string>/tmp/skhd.err</string>

Redirects stdout and stderr. Watch these files with tail -f /tmp/skhd.err | nl

Installing SSHFS on Mac

To set up ssh filesystem (sshfs) on a mac, follow these steps on the client:

$ brew install --cask osxfuse

Installs osxfuse. This is an open source tool to extend your mac's fs support

https://osxfuse.github.io/
$ curl https://github.com/osxfuse/sshfs/releases/download/osxfuse-sshfs-2.5.0/sshfs-2.5.0.pkg

Recently brew removed sshfs from its supported casks, since it relies on closed source code. Instead, you'll need to install it directly from the download link

See ssh_notes for using SSHFS

OSA script

MacOS's GUI can often be controlled through the use of Apple's osascript. Notably, this can allow shell programs to give GUI notifications

osascript -e 'display notification "'"${message}"'

Sends the system notification with the contents of $message

osascript -e 'display notification "'"${msg}"'" with title "Skhd"'

Adds a "Skhd" as a title to the notification

osascript -e 'display notification "'"${msg}"'" with title "Skhd" subtitle
"Could not save image"'

Further adds a subtitle for the notification

afplay $(defaults read .GlobalPreferences.plist \
    | awk '/sound.beep.sound"/ { gsub(/(.*= ")|(";)/, "", $0); print }')

Plays the default system error sound through the current audio output device

FreeBSD corner

Keep in mind that MacOS is based on a really old FreeBSD and NetBSD kernel, so many sections here will somewhat apply to Macs as well

Users and groups

Various commands for managing system permissions. Many can be, at least somewhat, run the user themselves with their password

# adduser
# rmuser
$ chpass  # edit user account settings, like login name and expiry
$ passwd  # change a user's password
$ pw      # a cli frontend for the settings files above. More advanced

https://docs.freebsd.org/en/books/handbook/basics/#users-modifying

/etc/group
$ id emiliko

Shows groups a user belongs to. User seems to implicitly belong to their group

rwxr-x---x  .
rwxr-x-r--  secret_file
rwxr-x-rw-  no_touching

Oddly, the x on the directory here means means all other users:

• Can cd into the directory

• Cannot ls in this directory

• Can read the file secret_file using something like vim secret_file

• Can write to no_touching. Vim can only do this with :x! not :w!

  service sshd restart

Reboots the ssh daemon. Users connected through ssh won't lose connection, if the reboot is successful [//]: # ex: set ft=markdown:tw=80: