Here are four great tools for recording screencasts on GNU/Linux:
- Open Broadcaster Software
Open Broadcaster Software
OBS (Open Broadcaster Software) is the heavy-weight of screencasting tools. It supports multiple platforms: GNU/Linux, Windows and Mac OS X. It can be used for more than recording, you can use it with YouTube or Twitch to stream videos live. You can include your webcam as a source for a more engaging presentation or just have the code on display.
Byzanz is a command-line tool. You can set options like the duration and delay of the recording. It can record into GIF or OGV/OGG formats.
Istanbul is a GUI-based tool. It sits in your tray and all you have to do is click on it to start recording. Click again and it stops recording and you can save the video.
recordMyDesktop is a great little tool that has a GTK and Qt frontend.