A working minimum.
WHAT TO LEARN
Moving around the file system Listing files and their permissions Viewing a file's contents Editing a file Checking disk space Checking running processes Checking memory use Restarting a service Viewing logs
WHY THESE
They cover diagnosis. Most incidents begin with looking at a log or checking whether something is running.
WHAT NOT TO RUN
Anything you do not understand Anything with recursive deletion Anything a stranger on a forum pasted
THE COMMAND THAT DESTROYS SERVERS
Recursive deletion from the wrong directory.
Check where you are before deleting anything.
BEFORE ANY CONFIGURATION CHANGE
Copy the original file first. Restoring from a copy takes seconds.
FOR LEARNING
Practise on a test server, not on one carrying live sites.
WHAT TO KEEP
A note of the commands you use rarely. You will not remember them.
