To start the vi editor and edit the file, use the following syntax:

$ vi <filename>

If the file exits with the specified filename, it will be opened and its contents are displayed in Command Mode. If the file does not exist, vi creates the file when it is saved on the disk for the first time. By default, vi uses an unnamed temporary buffer where the file is edited, until its contents are saved to disk. Now, let's understand the workings of vi in different modes in detail.