asciinema is a tool to record terminal sessions and share them as videos. But unlike many other tools that provide this functionality, ascinema does a very smart thing – instead of encoding the session into a video it interactively replays it in a text mode, which allows one to select and copy-paste commands and outputs from the playback. The resulting “video” is also much lighter and faster than it would be if encoded into a video stream.
This is great for demos, tutorials, and other more technical scenarios. The website also has a collection of recent and featured public screencasts.