I think this example will help you in understanding this more simply.
Path differences in Windows
Windows absolute path C:\Windows\calc.exe
Windows non absolute path (relative path) calc.exe
In the above example, the absolute path contains the full path to the file and not just the file as seen in the non absolute path. In this example, if you were in a directory that did not contain "calc.exe" you would get an error message. However, when using an absolute path you can be in any directory and the computer would know where to open the "calc.exe" file.
Path differences in Linux
Linux absolute path /home/users/c/computerhope/public_html/cgi-bin
Linux non absolute path (relative path) /public_html/cgi-bin
In these example, the absolute path contains the full path to the cgi-bin directory on that computer. How to find the absolute path of a file in Linux Since most users do not want to see the full path as their prompt, by default the prompt is relative to their personal directory as shown above. To find the full absolute path of the current directory use the pwd command.
It is a best practice to use relative file paths (if possible).
When using relative file paths, your web pages will not be bound to your current base URL. All links will work on your own computer (localhost) as well as on your current public domain and your future public domains.