The macOS Console application is a system-wide viewer for debug messages and log files. You can use it to locate errors in applications or just get an idea of what's going on in your system.
Most of the elements of this application are not intended to be viewed by the average user, they are intended for developers who better understand the macOS operating system. Warnings and errors are very common during normal use of your computer. So do not worry if you see a lot here.
Reading the console
You can launch the console application from Spotlight by pressing Command + Space and searching for it, or from the Utilities folder in your Applications directory. (Open the Finder and select "Applications" to find it.)
The first thing you will see is the console itself. This records each message sent by the processes and services running on your system. It is updating very quickly. You will need to sort if you want to understand.
In the toolbar, a button called "Now" automatically scrolls the window as new messages arrive. This can be useful if you are trying to debug in real time.
You can also choose to display only errors and faults, which will filter all that is no red or yellow dot, and will only show the important things you might want to see.
There is also a search bar here, which has the added functionality of being able to search by different parameters. Just type something, press Enter, then change the setting from the "All" drop-down menu:
You can use this option to refine the console and display only relevant messages for your problem.
Another view is the "Activities" panel, which will sort the console messages according to the activity they are associated with:
These are arranged in hierarchical order, so you will need to click on the white "+" button next to each one to expand it.
The newspaper viewer
The logs in your system work as more detailed and persistent console messages. You'll find them in the "Reports" section of the sidebar.
The logs are divided into different categories and you will find that most user-level applications have their logs in "~ / Library / Logs", divided by the application. Lower-level processes can have their names in "/ Library / Logs" or "/ var / log". They all exist on the disc too. You can browse these folders to copy the file itself if you have to send it to someone else. .
There are also the categories "System Reports" and "User Reports", which group the system process and user application logs.