Send command to another user's screen terminal

Question

I have two users; user1 and user2. I have a bash script run by user1, that needs to run a command on a screen terminal started by user2. Suggestions? Thanks Max

Answer 1

Do you want it to look as if user2 typed the command?

In the case of screen, you can use

screen -S user2/sessionname -p windowname -X "stuff ~user1/somescript.sh
"

This will type the text ~user1/somescript.sh (referring to a file in user1's home directory) to a specific window of the given screen session.

(Yes, the second " must be in a new line. Alternatively, use $'stuff blah\n')

To do this, you will need to have write access to user2/sessionname; read screen's manual page for description of multiuser and acladd.

---

In the generic "run stuff on another tty" case, you can use writevt /dev/pts/X sometext; the writevt tool is part of console-tools package. If your distro uses kbd instead, get writevt.c. This is specific to Linux.

Or do you just want user2 to see the output?

./somescript.sh >& /dev/pts/X

where /dev/pts/X is the tty device that belongs to user2's screen.

You will need write access; this can be given by user2 with chmod/setfacl, or you can use sudo.

(>& file is equivalent to > file 2>&1, which redirects both stdout and stderr to the given file.)