Making changes without breaking things.
THE RULE
Copy before you edit. Always.
Name the copy clearly: filename.php.backup, with today's date.
WHY
A single character error in a configuration file can take the whole site down.
WHAT TO BE ESPECIALLY CAREFUL WITH
.htaccess: a syntax error causes a 500 on every page wp-config.php: an error causes a blank page
Any PHP file: a missing bracket breaks it
AFTER EDITING
Load the site immediately and check.
Do not edit several files and then check.
IF IT BREAKS
Restore the copy. That is why you made it.
WHAT NOT TO EDIT
Core application files. Changes are lost on update and may break things.
Use the proper extension mechanism instead: a child theme, a plugin, a custom directory.
FOR LARGER CHANGES
Test on a staging copy first.
WHAT TO NEVER PASTE
Code from an unfamiliar source into a live site.
