Acceleration

Disabling

defaults write .GlobalPreferences com.apple.mouse.scaling -1

Note: Log out to take effect. If you change Tracking Speed under System Preferences, it will undo this fix. Only affects the mouse, not the trackpad.

Re-enabling

Under System Preferences → Mouse, change Tracking Speed.

Trackpad acceleration

defaults write .GlobalPreferences com.apple.trackpad.scaling -1

Works the same way, but only affects trackpads.

References

• Disabling mouse acceleration (stackoverflow.com)