hello,I want to execute a screen in shell, and execute command form the screen, How can I do it, thanks

[zheng senlin]

fivetrees ~ # cat hello.sh 

#!/bin/bash

exec screen -dmS hello     # I have open a screen in the background

#exec screen -r hello  /root/b.sh   # I want to execute /root/b.sh on the screen hello，How can I do it？ thanks

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