How to edit/save a file through Ubuntu Terminal

For editing use

vi galfit.feedme //if user has file editing permissions

or

sudo vi galfit.feedme //if user doesn't have file editing permissions

For inserting

Press i //Do required editing

For exiting

Press Esc

    :wq //for exiting and saving
    :q! //for exiting without saving

If you are not root user then, use following commands:

There are two ways to do it -

1.

sudo vi path_to_file/file_name

Press Esc and then type below respectively

:wq //save and exit
:q! //exit without saving

2. sudo nano path_to_file/file_name

When using nano: after you finish editing press ctrl+x then it will ask save Y/N.
If you want to save press Y, if not press N. And press enter to exit the editor.

Normal text editors are nano, or vi.

For example:

root@user:# nano galfit.feedme

or

root@user:# vi galfit.feedme