GIF screencasting; the UNIX way

To take a *static screenshot* of a selected part of my screen, I often use scrot with -s shot.png. This is great for adding illustrations to StackExchange posts. I even found this script to automatically upload such a screenshot to *Imgur.com* and put a link in my X clipboard! Let's turn this up to *twelve* : **How do I *similarly* create a GIF screencast?** There *are* programs like recordmydesktop, byzanz & co as discussed on Ask Ubuntu that aim to be "user friendly", but in my experience are buggy, inefficient, mostly unscriptable and unsuited for little one-off things like this. I just want to select an area and record a GIF, with a console command I can understand, not some arcane unscriptable GUI monstrosity. How can I do this?