kaishin-r

# Create a directory named "Sublime Text 3 Sync" under iCloud Drive
mkdir ~/Library/Mobile\ Documents/com~apple~CloudDocs/SubLime\ Text\ 3\ Sync

# Enter Sublime Text 3's directory
cd ~/Library/Application\ Support/Sublime\ Text\ 3/

# Move "Installed Packages" directory to iCloud Drive and make a link
mv Installed\ Packages/ ~/Library/Mobile\ Documents/com~apple~CloudDocs/SubLime\ Text\ 3\ Sync/
ln -s ~/Library/Mobile\ Documents/com~apple~CloudDocs/SubLime\ Text\ 3\ Sync/Installed\ Packages