The shell path for a user in OSX is a set of locations in the filing system whereby the user can use certain applications, commands and programs without the need to specify the full path to that command or program in the Terminal. This will work in all OSX operating systems.
You can find out whats in your path by launching Terminal in Applications/Utilities and entering:
Adding in a Permanent Location
To make the new path stick permanently you need to create a .bash_profile file in your home directory and set the path there. This file control various Terminal environment preferences including the path.
Create the .bash_profile file with a command line editor called nano
Add in the above line which declares the new location /Users/ofir/Library/Android/sdk/platform-tools as well as the original path declared as $PATH.
So now when the Terminal is relaunched or a new window made and you check the the path by
You will get the new path at the front followed by the default path locations, all the time