nano and vi.
WHAT nano IS
A simple editor, with commands shown at the bottom of the screen.
WHY IT SUITS MOST WORK
It behaves as people expect, and it is on almost every system.
WHAT THE ESSENTIAL KEYS ARE
Control and O to save Control and X to exit Control and W to search Control and K to cut a line
WHAT vi OR vim IS
A modal editor, present on every Unix system without exception.
WHY YOU MUST KNOW THE MINIMUM
Some systems have nothing else, including rescue environments.
WHAT THE MODES ARE
Normal, where keys are commands Insert, where keys are text
HOW TO ENTER INSERT MODE
Press i.
HOW TO LEAVE IT
Press escape.
HOW TO SAVE AND QUIT
Colon, then w and q, then enter.
HOW TO QUIT WITHOUT SAVING
Colon, then q and an exclamation mark.
WHAT TO DO BEFORE EDITING ANY CONFIGURATION
Copy the file to a backup with a dated name.
WHY
It is the only way to return to a working state quickly.
WHAT TO CHECK AFTER EDITING
That the service accepts the file, using its own test command where one exists.
WHAT TO NEVER DO
Restart a service with an untested configuration during business hours.
