The newest command line user in our family is 7. I gave her a Raspberry Pi last Christmas and loaded one thing; a python shell "PlayOS" that I wrote to make everything a three or four letter command. The idea is to improve her reading and writing/typing by putting everything she wants a few keystrokes away on the command line.
So far we have:
music - plays a random tune from her music collection
music abba - selects something more specific
see - shows something visual, for example;
see me - random photos from the holiday album
see octonauts - an undersea cartoon plays
read - stories and rhymes
say - make the computer speak (festival - which she calls robot
voice)
Basically, each time she expresses an interest I add a python tuple
which is a parsing template like alias + exec. After that she
memorises the command. By 9 I expect her to have mastered a computer
by typing, including sending emails to mom and dad etc. When she's had
enough she knows the poweroff command - which it's own kind of fun.Most of her friends drag their fingers over images on tablets. They get into a tantrum if it's taken away from them. They are addicts before they are 10.
Hopefully I'm helping build a life-long skill, but I dread the day her friends, pawing at screen like retarded monkeys, tell her that phones are better :)
Yes, there are physiological reasons to limit screen time too. But that's not my threat model at present. Time to boredom on PlayOS is always less than 1 hour.