Almost all interaction with Vagrant is done through the command-line interface.
The interface is available using the
vagrant command, and comes installed with Vagrant automatically. The
vagrant command in turn has many subcommands, such as
vagrant destroy, etc.
If you run
vagrant by itself, help will be displayed showing all available subcommands. In addition to this, you can run any Vagrant command with the
-h flag to output help about that specific command. For example, try running
vagrant init -h. The help will output a one sentence synopsis of what the command does as well as a list of all the flags the command accepts.
In depth documentation and use cases of various Vagrant commands is available by reading the appropriate sub-section available in the left navigational area of this site.