$ source activate
What does ‘source’ do ?
Source is a bash shell built-in command that executes the content of the file passed as argument, in the current shell
Running the command
source on a script executes the script within the context of the current process. This means that environment variables set by the script remain available after it’s finished running. This is in contrast to running a script normally, in which case environment variables set within the newly-spawned process will be lost once the script exits.
You can source any runnable shell script. The end effect will be the same as if you had typed the commands in the script into your terminal.