Anything that happens on your system is logged and written to a log file. Log files are stored in the following directory
/var/log
Log files are just like standard text files and end with the extension .log. Because they are like text files, log files can be viewed through a standard text editor locally, or through the terminal or remotely using putty.
An example might be that you want to check a log file on a remote system by using a graphical terminal program like Putty, where you don't have access to a remote desktop.
Also accessing log files through programs like putty use less resources and is also quicker than using a remote desktop.
To view a log file, open your terminal and enter the following command to view the log directory
cd /var/log
dir
To view a log file in the terminal for example the gufw.log file we can issue the less command in the terminal