What tools do you use for command line editing? [edited to be more like a question.] 

I have been producing video using a combination of ffmpeg, mencoder and graphicsmagick for several years. Mostly it is because of not only the sorry state of affairs of GUI editing tools on linux, but also since I prefer to use the command line and scripts more than clumsy crashy interfaces.

[/edit]

I investigated the MELT CLI after stumbling across a couple of youtube videos showing how it works.

As opposed to ffmpeg, it is FRAME-PERFECT, allows for simple concatenation of files or even clips within multiple files, transitions are incredibly easy and the usage of video and sound filters is intuitive (once you have wrapped your head around the syntax). In fact, you can even script effects with html5! 

Here is an example that would provide both an audio and video transition between clip1 and clip2 and create an mp4.

$ melt clip1.dv clip2.dv -mix 25 -mixer luma -mixer mix:-1 \
  -consumer avformat:clip1and2_mixed.mp4


From their webpage regarding their system / plugins:

FFmpeg for audio/video decoding and encoding
swfdec Flash decoder
WebVfx for HTML5-based graphics/animation generation
GTK+ and Qt for image loading and text rendering
LADSPA audio plugins
SoX audio effects
libsamplerate audio resampler
JACK audio routing
frei0r video plugins
SDL for desktop audio/video output 


Note:
I am not knocking ffmpeg and I am not affiliated with MLT or MELT.

http://www.mltframework.org/bin/view/MLT/Projects

http://www.mltframework.org/bin/view/MLT/MltMelt
Video editing is a very visual workflow, you need to see your result at all times, instantly, to be effective in your daily job.
Working with a CLI is rather counter intuitive and makes it hard to make creative decisions.

Frameworks like these are great to make programs on top of them and to automate video processing but are tedious to use in standard video production and animation workflows.
It's a matter of what you want to do, not whether its a powerful tool or not.