Shell Programming and Scripting

Hi,

How can I check and modify /etc/ssh/sshd_config parameters in a script? I'll particular to check and enable / disable PasswordAuthentication and PubkeyAuthentication. I know I can edit sshd_config by vi, but for some reason we need change it in a script.

Thank you.

hce

In case you aren't aware, you can override sshd_config settings with command options.

Regards,
Alister

Thanks Alister, could you please give an example of how to change "PasswordAuthentication = yes" in the command options?

Thank you.

Kind regards.

From man ssh :

Thanks mirni, but I tried:


ssh -o PasswordAuthentication=yes root@remote_vm

It did not work. Not clear if we are in the same page. I actually asked how to change the /etc/ssh/sshd_config which defines "PasswordAuthentication no" by command line in script in the remote_vm machine. I guess the ssh -o option is only to change /etc/ssh/ssh_config setting, is it correct?

Thank you.

Kind regards.

Have a look at your sshd man page. The answer is there.

And, in case it isn't obvious, an ssh client can't override a server's settings. That would be very insecure.

Regards,
Alister

Yes, command line options are for ssh, and they override ssh_config.
For changing existing options in sshd_config you can use awk

Code:

file=/etc/ssh/sshd_config
cp -p $file $file.old &&
awk '
$1=="PasswordAuthentication" {$2="yes"}
$1=="PubkeyAuthentication" {$2="yes"}
{print}
' $file.old > $file

or do it in a shell loop

Code:

file=/etc/ssh/sshd_config
cp -p $file $file.old &&
while read key other
do
 case $key in
 PasswordAuthentication) other=yes;;
 PubkeyAuthentication) other=yes;;
 esac
 echo "$key $other"
done < $file.old > $file