Suppose you'd like to store the output of htop to a file. You can do it by taking a screenshot of a GNU Screen session:
$ screen -d -m -S screenshot htop $ sleep 1 $ screen -p 0 -S screenshot -X output $ screen -p 0 -S screenshot -X quit
Now the screenshot lives in output.0 in the current directory.
Adapted from this post on Stack Overflow.
