I was su'ed into a user to run a particular long running script. I wanted to use screen but I got the error message "Cannot open your terminal '/dev/pts/4' - please check."
So I Googled around and came across a forum post that instructed to run
$ script '/dev/null/'. I did so and then I could screen.
Why does this work? What is su doing that screen cannot run as the su'ed user? Why does re-directing 'script' to /dev/null do that is prevented otherwise? Is it using script to write a log as the original user to somewhere?