Echo to screen session and to file

Question

I want to execute the following command:

echo $RANDOM 2>&1 >> test.txt 

in this screen session:

screen -S test -X eval 'stuff "echo $RANDOM 2>&1 >> test.txt\015"'

However, instead of executing, it echoes the following:

echo  2>&1 >> test.txt

What am I doing wrong?

I want the echo command to not just to save its ouptut to test.txt, but to actually show that output to the screen as well.

Answer 1

You can do like this:

screen -S test -X exec bash -c 'echo RANDOM=$RANDOM 2>&1 >> test.txt'

If you want to see the output and save at the same time, you can use tee:

screen -S test -X exec bash -c 'echo RANDOM=$RANDOM 2>&1 | tee -a test.txt'

Answer 2

$ screen -S test -X stuff 'echo \$RANDOM >> /tmp/test 2>&1\n'

Or if you want to duplicate the output and manage it without tee by some reason

$ screen -S shell -X stuff 'echo \$RANDOM 2>&1 | while read; do printf "%s\\n" "\$REPLY"; printf "%s\\n" "\$REPLY" >> /tmp/test; done\n'

I assume you want redirect to file both stdin and stdout and your 2>&1 >> test.txt was an accidentally mistake.