Change macOS Dock Icon Size

Set to an Integer Value (default is 64) #

Dock icon size of 32 pixels.

defaults write com.apple.dock "tilesize" -int "32" && killall Dock

Dock icon size of 48 pixels.

defaults write com.apple.dock "tilesize" -int "48" && killall Dock

Read Current Value #

defaults read com.apple.dock "tilesize"

Reset to Default #

defaults delete com.apple.dock "tilesize" && killall Dock