% osx, mac os

# Copy <file_or_dir> to <target_path>, and remove all target files and directories `@` attribute
cp -RX <file_or_dir> <target_path>

# Remove <file_or_dir>'s `@` attribute
xattr -rc <file_or_dir>

# Lock system
pmset displaysleepnow

# Eject volume
diskutil eject '<eject_vol>'

# Show disk info
diskutil list

# Show partition info
diskutil info '<disk_dev>'

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

# Hide hidden files in Finder
defaults write com.apple.finder AppleShowAllFiles -bool false; \
   killall Finder

# Show items in desktop
defaults write com.apple.finder CreateDesktop -bool true; \
   killall Finder

# Hide items in desktop
defaults write com.apple.finder CreateDesktop -bool false; \
   killall Finder

# Set wallpaper
osascript -e 'tell application "Finder" to set desktop picture to POSIX file "<image_path>"'

$ file_or_dir: ls
$ image_path: find $HOME -maxdepth 3 -name "*.jpg" -o -name "*.jpeg" -o -name "*.png"
$ disk_dev: find /dev -maxdepth 1 -name "disk*s*"
$ eject_vol: find /Volumes ! -path /Volumes -maxdepth 1 -type d  -name "*"