To open Sublime Text from a command line or terminal in Mac OSX requires a small configuration change but is possible.

Identify the executable

Try this command from the command prompt:

/Applications/Sublime\ Text.app/Contents/SharedSupport/bin/subl

It should open Sublime Text from the command line. This path might be slightly different on some installs like it may say Sublime\ Text\ 2.app. So if you get no such file then look around a little to find the right path.

From the command line confirm that /usr/local/bin is in your path by doing the following command:

echo $PATH

If it is there then create a symbolic link in that directory that points to the subl program. Here is the command to do this:

sudo ln -s /Applications/Sublime\ Text.app/Contents/SharedSupport/bin/subl /usr/local/bin/subl

This is the same path that we identified in step one.

After that you should be able to simply type subl at a command line prompt and open the program.

Using the command

To open a single file:
subl /path/to/filename.txt

To open a whole directory:
subl .

To see additonal command usage:
subl --help

Additional command line usage can be seen here:
subl command for ST2
subl command for ST3