I have this command
cat ~/.ssh/id_dsa.pub | ssh root@[my_server] "cat >> ~/.ssh/authorized_keys" How can I do the same thing but with sudo -iu user1 before the 2nd cat? That is, I want to change a user after having been logged in.
2 Answers
If you don't mind getting the key on the screen as well (it is the public key, so this is not much of a security issue), you should be able to use tee to avoid redirection troubles along the lines of
cat ~/.ssh/id_dsa.pub \ | ssh root@server 'sudo -i -u user1 tee -a ~user1/.ssh/authorized_keys' 
answered May 24, 2022 at 5:21
- 1End the remote
teecommand with>/dev/nulland you don't get the key written to stdoutCommentedMay 24, 2022 at 6:41 - @roaima ... or the pipeline, if you're ok with transferring the data to the local host just to throw it away. Also, the
catcould be replaced by an input redirection.– Kusalananda♦CommentedMay 24, 2022 at 6:57
Try this:
cat ~/.ssh/id_dsa.pub | ssh root@[my_server] $'sudo -i -u user1 bash -c "cat - >> ~/.ssh/authorized_keys"' 
- 1
- 1@Johsua It would interpret the string following as a "C string" and replace any
\nor\tetc. with literal newline or tab characters. However, in this instance, it would make absolutely no difference, so you may remove the$.– Kusalananda♦CommentedMay 23, 2022 at 21:28 - 1You could avoid the
bash -cby usingsudo -u user1 tee -a ~user1/.ssh/authorized_keys >/dev/null. Note that thecatis then also not needed.– Kusalananda♦CommentedMay 23, 2022 at 21:30
man ssh-copy-id.