Unveil hidden macOS (OS X) features
Mr.W 
Earlier this week, a bug in macOS High Sierra was discovered that made it possible to use the root user without a password. That could be dangerous in combination with malware.
Thankfully, Apple is resolving this bug within 24 hours with a security update. Only this has created a new problem that affects a select number of users. If you use file sharing within your own network, this may stop working. You can easily solve this problem with a Terminal command.
Sometimes it can happen when saving a document that you have to click first on the triangle next to the Location field to open the expanded save window. This can be very confusing, with the following command you can enable the expand save panel by default.
Since OS X 10.9 mavericks, the behavior of the power button has been changed. When you press the power button for about 2 seconds, it will put macOS (OS X) in stand-by (sleep) mode.
With the following command you can use the power button function as in previous versions of OS X. By showing a dialog box for turning off the Mac and more.
There is a Terminal command that you can use to quickly make your dock look like new again. Do you experience problems with the Dock on your Mac? The best you can do is to reset it to default settings.
The following Terminal command will reset your dock by removing any icons that you’ve added and removed. It’ll also reset the size of the dock, magnification settings, and its location.
File extensions (.jpg, .txt, .pdf, etc) are normally hidden by default in OS X. You can either set all extensions to be displayed through the following command:
Through the system preferences you can adjust the size of the Dock icons. Unfortunately, you can’t go larger than 256 pixels. With the following command you can change the size in different sizes.
TextEdit is a simple application for quickly writing text and notes. The text can be edited in RTF (Rich Text Format) mode, as well as plain text. With the following defaults write command you can enable plain text as default format in TextEdit.