I recently ran into an issue where I needed to demo a project without
actually being present for the demo. I thought about recording (into
some video format) a screencast of my terminal window and then having my
audience play it at the time of the demo. This would have worked just
fine, but, as I was browsing the internet searching for exactly how to
record a screencast of this nature, I ran across a blog
post
talking about how to play back terminal sessions using the output of the
script program. This piqued my interest for several reasons:
- I have used script many times to log results of tests.
- This method of recording a shell session is much more efficient than recording it into video because it only stores the actual text of the output as well as some timing information.
In order to “record” using script you store the terminal output and the
timing information to two different files using a command like the
following:
\
script -t 2> screencast.timing screencast.log
The -t in the command causes script to output timing data to standard
error. The 2> screencast.timing causes standard error to be
redirected to the file screencast.timing. The screencast.log
file will hold everything printed on the terminal during the course of
the screencast session.
After running the command, execute a few programs (ls,
echo "Hi Planet", etc…) and then type exit to end the session.
Now the screencast is stored in the two files. You can play back the
screencast using:
\
scriptreplay screencast.timing screencast.log
And Voila. As long as your target audience has a box with
script/scriptreplay installed then they can view your screencast!
I have included a screencast.timing
and a screencast.log file you can
download and use with scriptreplay if you would like to demo this out.
The files combined are under 5K in size for a 1 minute 40 second
screencast, however I think the actual size of the files depends more on
how much data was output rather than the length of the screencast.
Even better than using my screencast, create one yourself!
Enjoy!