System Configuration via defaults

The defaults command is macOS’s tool for reading and writing user preferences. Every application preference, system setting, and hidden configuration option is stored in property list (plist) files, and defaults gives you direct access to them. Mastering this command unlocks powerful system customization.

How Preferences Work

macOS stores preferences in plist files:

# User preferences
~/Library/Preferences/

# System-wide preferences (require sudo)
/Library/Preferences/

# Current host preferences (hardware-specific)
~/Library/Preferences/ByHost/

Each application has a domain (usually its bundle identifier):

# Finder preferences
~/Library/Preferences/com.apple.finder.plist

# Safari preferences
~/Library/Preferences/com.apple.Safari.plist

# Global preferences
~/Library/Preferences/.GlobalPreferences.plist
# Also accessible as NSGlobalDomain

Basic Usage

Reading Preferences

# Read all preferences for an app
$ defaults read com.apple.finder
{
    AppleShowAllExtensions = 1;
    AppleShowAllFiles = 1;
    CreateDesktop = 1;
    ...
}

# Read specific key
$ defaults read com.apple.finder AppleShowAllFiles
1

# Read from global domain
$ defaults read NSGlobalDomain AppleShowAllExtensions
1

# Read a specific plist file
$ defaults read ~/Library/Preferences/com.apple.finder.plist

# List all domains
$ defaults domains
com.apple.AMPDevicesAgent, com.apple.AMPLibraryAgent, com.apple.AddressBook, ...

# Find domains containing "apple"
$ defaults domains | tr ',' '\n' | grep -i apple

Writing Preferences

# Write a boolean value
$ defaults write com.apple.finder AppleShowAllFiles -bool true

# Write an integer
$ defaults write com.apple.dock autohide-delay -int 0

# Write a float
$ defaults write com.apple.dock autohide-time-modifier -float 0.5

# Write a string
$ defaults write com.apple.finder NewWindowTarget -string "PfLo"

# Write an array
$ defaults write com.apple.dock persistent-apps -array

# Write to global domain
$ defaults write NSGlobalDomain AppleShowAllExtensions -bool true

# Write to current host (hardware-specific)
$ defaults -currentHost write com.apple.screensaver idleTime -int 300

Deleting Preferences

# Delete a specific key (revert to default)
$ defaults delete com.apple.finder AppleShowAllFiles

# Delete entire domain (dangerous!)
$ defaults delete com.apple.finder

# Be careful - there's no undo!

Data Types

The defaults command supports these data types:

Essential Finder Customizations

# Show hidden files
$ defaults write com.apple.finder AppleShowAllFiles -bool true
$ killall Finder

# Show all file extensions
$ defaults write NSGlobalDomain AppleShowAllExtensions -bool true
$ killall Finder

# Show path bar
$ defaults write com.apple.finder ShowPathbar -bool true

# Show status bar
$ defaults write com.apple.finder ShowStatusBar -bool true

# Show full POSIX path in title bar
$ defaults write com.apple.finder _FXShowPosixPathInTitle -bool true

# Keep folders on top when sorting by name
$ defaults write com.apple.finder _FXSortFoldersFirst -bool true

# Default to list view
$ defaults write com.apple.finder FXPreferredViewStyle -string "Nlsv"
# Nlsv = List, icnv = Icon, clmv = Column, glyv = Gallery

# Disable warning when changing file extension
$ defaults write com.apple.finder FXEnableExtensionChangeWarning -bool false

# Disable warning when emptying Trash
$ defaults write com.apple.finder WarnOnEmptyTrash -bool false

# Don't create .DS_Store on network volumes
$ defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true

# Don't create .DS_Store on USB volumes
$ defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true

# Show icons on desktop
$ defaults write com.apple.finder ShowExternalHardDrivesOnDesktop -bool true
$ defaults write com.apple.finder ShowHardDrivesOnDesktop -bool false
$ defaults write com.apple.finder ShowMountedServersOnDesktop -bool true
$ defaults write com.apple.finder ShowRemovableMediaOnDesktop -bool true

# New Finder window shows home folder
$ defaults write com.apple.finder NewWindowTarget -string "PfHm"
$ defaults write com.apple.finder NewWindowTargetPath -string "file://${HOME}/"
# PfHm = Home, PfLo = Computer, PfDe = Desktop, PfDo = Documents

# Restart Finder to apply changes
$ killall Finder

Dock Customizations

# Auto-hide the Dock
$ defaults write com.apple.dock autohide -bool true

# Remove auto-hide delay
$ defaults write com.apple.dock autohide-delay -float 0

# Speed up auto-hide animation
$ defaults write com.apple.dock autohide-time-modifier -float 0.3

# Change Dock icon size
$ defaults write com.apple.dock tilesize -int 48

# Enable magnification
$ defaults write com.apple.dock magnification -bool true
$ defaults write com.apple.dock largesize -int 64

# Position: left, bottom, right
$ defaults write com.apple.dock orientation -string "left"

# Minimize windows into application icon
$ defaults write com.apple.dock minimize-to-application -bool true

# Minimize effect: genie, scale, suck
$ defaults write com.apple.dock mineffect -string "scale"

# Don't show recent applications
$ defaults write com.apple.dock show-recents -bool false

# Clear persistent apps (empty Dock)
$ defaults write com.apple.dock persistent-apps -array

# Add spacer tiles
$ defaults write com.apple.dock persistent-apps -array-add '{"tile-type"="spacer-tile";}'

# Restart Dock to apply changes
$ killall Dock

Screenshot Customizations

# Change screenshot location
$ defaults write com.apple.screencapture location -string "${HOME}/Screenshots"

# Change screenshot format (png, jpg, gif, pdf, tiff)
$ defaults write com.apple.screencapture type -string "png"

# Disable shadow in screenshots
$ defaults write com.apple.screencapture disable-shadow -bool true

# Include date in screenshot name
$ defaults write com.apple.screencapture include-date -bool true

# Change screenshot name prefix
$ defaults write com.apple.screencapture name -string "screenshot"

# Apply changes
$ killall SystemUIServer

Safari Customizations

# Enable Develop menu
$ defaults write com.apple.Safari IncludeDevelopMenu -bool true
$ defaults write com.apple.Safari WebKitDeveloperExtrasEnabledPreferenceKey -bool true

# Show full URL in address bar
$ defaults write com.apple.Safari ShowFullURLInSmartSearchField -bool true

# Disable auto-fill
$ defaults write com.apple.Safari AutoFillCreditCardData -bool false
$ defaults write com.apple.Safari AutoFillPasswords -bool false

# Enable "Do Not Track"
$ defaults write com.apple.Safari SendDoNotTrackHTTPHeader -bool true

# Don't open "safe" files after downloading
$ defaults write com.apple.Safari AutoOpenSafeDownloads -bool false

# Show favorites bar
$ defaults write com.apple.Safari ShowFavoritesBar -bool true

# Enable keyboard navigation
$ defaults write com.apple.Safari WebKitTabToLinksPreferenceKey -bool true

# Restart Safari to apply
$ killall Safari

System UI Customizations

# Expand save dialog by default
$ defaults write NSGlobalDomain NSNavPanelExpandedStateForSaveMode -bool true
$ defaults write NSGlobalDomain NSNavPanelExpandedStateForSaveMode2 -bool true

# Expand print dialog by default
$ defaults write NSGlobalDomain PMPrintingExpandedStateForPrint -bool true
$ defaults write NSGlobalDomain PMPrintingExpandedStateForPrint2 -bool true

# Disable auto-correct
$ defaults write NSGlobalDomain NSAutomaticSpellingCorrectionEnabled -bool false

# Disable auto-capitalization
$ defaults write NSGlobalDomain NSAutomaticCapitalizationEnabled -bool false

# Disable smart quotes
$ defaults write NSGlobalDomain NSAutomaticQuoteSubstitutionEnabled -bool false

# Disable smart dashes
$ defaults write NSGlobalDomain NSAutomaticDashSubstitutionEnabled -bool false

# Disable "natural" scrolling
$ defaults write NSGlobalDomain com.apple.swipescrolldirection -bool false

# Set key repeat rate (lower = faster)
$ defaults write NSGlobalDomain KeyRepeat -int 2

# Set delay until repeat (lower = shorter)
$ defaults write NSGlobalDomain InitialKeyRepeat -int 15

# Enable full keyboard access (Tab through all controls)
$ defaults write NSGlobalDomain AppleKeyboardUIMode -int 3

# Use dark mode
$ defaults write NSGlobalDomain AppleInterfaceStyle -string "Dark"

# Use light mode (delete dark mode setting)
$ defaults delete NSGlobalDomain AppleInterfaceStyle

# Set accent color (Graphite = -1, Red = 0, Orange = 1, etc.)
$ defaults write NSGlobalDomain AppleAccentColor -int 4

Menu Bar and Control Center

# Show battery percentage
$ defaults write com.apple.menuextra.battery ShowPercent -string "YES"

# Show Bluetooth in menu bar
$ defaults write com.apple.controlcenter "NSStatusItem Visible Bluetooth" -bool true

# Show Sound in menu bar
$ defaults write com.apple.controlcenter "NSStatusItem Visible Sound" -bool true

# Show Wi-Fi in menu bar
$ defaults write com.apple.controlcenter "NSStatusItem Visible WiFi" -bool true

# Clock format (customize as needed)
$ defaults write com.apple.menuextra.clock DateFormat -string "EEE d MMM HH:mm:ss"

# Show date in menu bar
$ defaults write com.apple.menuextra.clock ShowDate -int 1

# Flash time separators
$ defaults write com.apple.menuextra.clock FlashDateSeparators -bool false

Text Edit Customizations

# Default to plain text
$ defaults write com.apple.TextEdit RichText -int 0

# Open and save as UTF-8
$ defaults write com.apple.TextEdit PlainTextEncoding -int 4
$ defaults write com.apple.TextEdit PlainTextEncodingForWrite -int 4

Disk Utility

# Show all devices
$ defaults write com.apple.DiskUtility SidebarShowAllDevices -bool true

# Enable advanced features
$ defaults write com.apple.DiskUtility advanced-image-options -bool true

Mission Control and Spaces

# Don't automatically rearrange Spaces
$ defaults write com.apple.dock mru-spaces -bool false

# Group windows by application
$ defaults write com.apple.dock expose-group-apps -bool true

# Hot corners (actions: 0=none, 2=Mission Control, 3=App Windows, 4=Desktop, etc.)
# Bottom left corner: Mission Control
$ defaults write com.apple.dock wvous-bl-corner -int 2
$ defaults write com.apple.dock wvous-bl-modifier -int 0

# Bottom right corner: Desktop
$ defaults write com.apple.dock wvous-br-corner -int 4
$ defaults write com.apple.dock wvous-br-modifier -int 0

$ killall Dock

Security and Privacy

# Require password immediately after sleep
$ defaults write com.apple.screensaver askForPassword -int 1
$ defaults write com.apple.screensaver askForPasswordDelay -int 0

# Enable firewall
$ sudo defaults write /Library/Preferences/com.apple.alf globalstate -int 1

# Enable firewall stealth mode
$ sudo defaults write /Library/Preferences/com.apple.alf stealthenabled -int 1

# Disable crash reporter dialog
$ defaults write com.apple.CrashReporter DialogType -string "none"

Reading Preferences from Different Sources

# Read from app container
$ defaults read ~/Library/Containers/com.apple.Safari/Data/Library/Preferences/com.apple.Safari.plist

# Read system-wide preferences
$ sudo defaults read /Library/Preferences/com.apple.loginwindow

# Read from specific plist file
$ defaults read /System/Library/CoreServices/SystemVersion.plist

# Read raw plist (bypassing defaults)
$ plutil -p ~/Library/Preferences/com.apple.finder.plist

# Convert binary plist to XML
$ plutil -convert xml1 -o - ~/Library/Preferences/com.apple.finder.plist

Finding Hidden Preferences

# Watch for preference changes
$ defaults read com.apple.finder > before.txt
# Change a setting in the GUI
$ defaults read com.apple.finder > after.txt
$ diff before.txt after.txt

# Use defaults to export, compare
$ defaults export com.apple.finder - > finder_prefs.xml

# Find keys containing a term
$ defaults read com.apple.finder | grep -i "show"

# Read all domains, search for term
$ defaults domains | tr ',' '\n' | while read domain; do
    defaults read "$domain" 2>/dev/null | grep -l "searchterm" && echo "$domain"
done

Applying Changes: The Restart Requirement

Different changes require different restarts:

Backup and Restore Preferences

# Export preferences
$ defaults export com.apple.finder ~/finder-backup.plist

# Import preferences
$ defaults import com.apple.finder ~/finder-backup.plist

# Backup all preferences
$ cp -R ~/Library/Preferences ~/preferences-backup

# Export to human-readable format
$ defaults export com.apple.finder - | plutil -convert xml1 -o ~/finder-backup.xml -

Complete Setup Script Example

#!/bin/bash
# macOS customization script

echo "Configuring macOS preferences..."

# Close System Preferences to prevent conflicts
osascript -e 'tell application "System Preferences" to quit'

# ========== Finder ==========
defaults write com.apple.finder AppleShowAllFiles -bool true
defaults write com.apple.finder AppleShowAllExtensions -bool true
defaults write com.apple.finder ShowPathbar -bool true
defaults write com.apple.finder ShowStatusBar -bool true
defaults write com.apple.finder _FXShowPosixPathInTitle -bool true
defaults write com.apple.finder _FXSortFoldersFirst -bool true
defaults write com.apple.finder FXEnableExtensionChangeWarning -bool false
defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true

# ========== Dock ==========
defaults write com.apple.dock autohide -bool true
defaults write com.apple.dock autohide-delay -float 0
defaults write com.apple.dock autohide-time-modifier -float 0.3
defaults write com.apple.dock tilesize -int 48
defaults write com.apple.dock show-recents -bool false
defaults write com.apple.dock mineffect -string "scale"

# ========== Screenshots ==========
mkdir -p "${HOME}/Screenshots"
defaults write com.apple.screencapture location -string "${HOME}/Screenshots"
defaults write com.apple.screencapture type -string "png"
defaults write com.apple.screencapture disable-shadow -bool true

# ========== Input ==========
defaults write NSGlobalDomain KeyRepeat -int 2
defaults write NSGlobalDomain InitialKeyRepeat -int 15
defaults write NSGlobalDomain AppleKeyboardUIMode -int 3
defaults write NSGlobalDomain NSAutomaticSpellingCorrectionEnabled -bool false
defaults write NSGlobalDomain NSAutomaticQuoteSubstitutionEnabled -bool false
defaults write NSGlobalDomain NSAutomaticDashSubstitutionEnabled -bool false

# ========== Safari ==========
defaults write com.apple.Safari IncludeDevelopMenu -bool true
defaults write com.apple.Safari ShowFullURLInSmartSearchField -bool true
defaults write com.apple.Safari AutoOpenSafeDownloads -bool false

# ========== Security ==========
defaults write com.apple.screensaver askForPassword -int 1
defaults write com.apple.screensaver askForPasswordDelay -int 0

# ========== Apply Changes ==========
echo "Restarting affected applications..."
for app in "Finder" "Dock" "SystemUIServer" "Safari"; do
    killall "${app}" &> /dev/null
done

echo "Done. Some changes may require logout/restart."

Summary

The defaults command gives you complete control over macOS preferences:

Key domains:

Remember to restart the appropriate application or service after making changes. With defaults, you can automate your entire macOS setup and maintain consistent configurations across machines.