You may have been already familiar with the man command which is used to see the manual for a linux command. It is useful but can be too verbose sometimes depending on your use case so here comes another tool tldr which derived it's name from the famous too long did not read. Its tagline is Simplified and community-driven man pages and it aims to provide a simplified version of the man pages. Aside from being simplified it also provides examples on the use cases of a command. It is community-driven which means if you can just send a PR on it's repository for any missing data or if you want to improve existing information.

I won't consider tldr a replacement for the man pages since there are still cases when you would like to know deeper information. However, it is an effective tool since it gives you what you need right away most of the time. I see myself using it often from now :)