The vi editor (visual editor) is a screen editor which is available on almost all unix system.once you have learned vi editor.you will find that is a fast and powerful editor.vi has no menus but instead uses combinations of keystrokes in order to accomplish commands.
Keyboard-based editors use a keyboard for two different operations,to specify editing commands and to receive character input.used for editing commands,certain keys perform deletions,some execute change,and others perform cursor movement.used for character inpute,keys represent characters that can be entered into the file being edited.
Usually,these two different functions are divided among,different keys on the keyboard.alphabetic keys are reserved for character input,while function keys and control keys specify editing commands.
To start using vi editor,at the linux prompt type folloed by a file name.if you wish to edit an existing file,type in its name,if you are creating a new file type in the name you wish to give to the new file.
then press enter.you will see a screen similar to the one below which shows blank lines with tildes and the name and status of the file.
$vi file1 - [Enter]