When setting up a server for the first time with Ansible you will need to pass ssh credentials to Ansible directly to set up ssh keys. This is done by the use of the sshpass program which allows Ansible to pass your user credentials directly to ssh in order to open a connection to the server. The sshpass program is easily installed on Linux systems with the apt or yum package managers, but on OSX you will need to install it manually.
Adding an alias to your system is a good way of saving time when remembering complex commands. You can reduce a command down to a quick two letter command that is easy to remember.
The alias command can be used to assign an alias on the fly. You can create an alias to 'ls -lah' by typing in the following into the command line.
alias ll="ls -lah"
Now, when you type 'll' (i.e. two lower case L's) you will actually run the command 'ls -la'.
Or you might want to do more complex things like running your selenium server.
alias selenium-server="java -jar ~/Development/selenium-server-standalone-2.25.0.jar"
To remove an alias you can use the unalias command to remove an alias from your system.