Hey all, I am trying to run a remote command to replace text in my sshd_config file. I want to be able to run it remotely to all of the servers I have. How would I run this sed command remotely? so far I have


ssh server 'sed -i 's/#PubkeyAuthentication/PubkeyAuthentication/g/' sshd_config'


Doesn't seem to want to work. Any help?


Eventually i want to be able to pull in a text file with all of the server names

ssh root@<server> "/bin/sed -e 's/#PubkeyAuthentication/PubkeyAuthentication/' /etc/ssh/sshd_config'>/etc/ssh/sshd_config1 && mv /etc/ssh/sshd_config1 /etc/ssh/sshd_config"

(one line) should do

Use a full path to the config file: /etc/ssh/sshd_config.

You need to login as root to do this. It isn't a good idea to allow root logins, especially if you use password authentication. I imagine that is what you are trying to fix.

Also consider:
UsePam yes
PermitRootLogin no
PubkeyAuthentication yes
ChallengeResponseAuthentication no

See the comments for "UsePam" in the /etc/ssh/sshd_config file. These settings only allow pubkey authentication and use PAM for session control. Another entry to consider is "AllowUsers" to only allow logins from certain users. The entries can also use the "user@host" form, which allows logins for (local)user @ (remote)host. Further info is in the ssh_config manpage.

You may need another sed command in the sed line. You can add sed commands in a oneliner by separating them with ";" or using the -e option before each command.

I actually had the full path to the ssh file. I will look at it again with the above suggestions thanks.



ssh root@<server> "/bin/sed -e 's/#PubkeyAuthentication/PubkeyAuthentication/' /etc/ssh/sshd_config'>/etc/ssh/sshd_config1 && mv /etc/ssh/sshd_config1 /etc/ssh/sshd_config"

This worked except I had to remove the one ' after sshd_config. Now how come I have to export it to another file and then move it? Why wouldn't just the command alone replace it like it does if ran locally?

The "-i" sed option will allow you to do in situ editing, so you don't need to redirect to a temporary file. The example given in #2 didn't use "-i". I'm not sure if "-i" is portable.
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