Run Sublime Text 3 and check version

The command to start Sublime Text:

subl

The command to see its version:

subl --version

The usual command for Sublime Text is subl:

From subl --help:

$ subl --help
Sublime Text build 3065

Usage: sublime_text [arguments] [files]         edit the given files
   or: sublime_text [arguments] [directories]   open the given directories

Arguments:
  --project <project>: Load the given project
  --command <command>: Run the given command
  -n or --new-window:  Open a new window
  -a or --add:         Add folders to the current window
  -w or --wait:        Wait for the files to be closed before returning
  -b or --background:  Don't activate the application
  -h or --help:        Show help (this message) and exit
  -v or --version:     Show version and exit

Filenames may be given a :line or :line:column suffix to open at a specific
location.

Hence, to get the version:

$ subl -v
Sublime Text Build 3065

As Glutanimate noted, you can get the version from the Help menu, from About Sublime Text: