URL shortener without database

I was pleasantly surprised by this SIMPLE URL Link Shortener. It works as advertised. It accepts a long URL and shortens it nicely to a six letter/digit code. The short URL is stored in a text file so no database is required. The instructions need tweaking to: Create a host website directory (folder) named url-short-txt. For example if your website address is www.yoursite.com then add a directory (folder) named url-short-txt so you can access the program with the line www.yoursite.com/url-short-txt. Copy all the included files to the url-short-text directory or folder. Then add a subdirectory (folder) to the url-short-txt directory named txt-db. That is where the text files with the original long URL is stored. The name of the text file contains the short URL. When someone clicks on the short URL the PHP script sends them to the long URL associated with the short URL text file. A new and unique text file is created for every long link you shorten. The link is "branded" with your website address and the name of the directory the script is stored in; url-short-txt. This is a simple, easy to install and use script. You can generate as many short URLs as you wish. Diagnostics are not included as that would require a database and a more complicated script. I am using PHP 8.0 and everything worked fine on a Windows 11 desktop and Mozilla Firefox browser. Thanks for an excellent script!