Sublime Text 3 ships with a CLI called subl. You will have to do a minor configuration though.
Firstly, check your $PATH by running: echo $PATH.
It should look like this:
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
Then copy this into terminal:
ln -s "/Applications/Sublime Text.app/Contents/SharedSupport/bin/subl" /usr/local/bin/subl
Now typing subl in the command line should open Sublime