wrapper command for sshd_config?

Question

Is there a command to set settings in sshd_config, instead of manually editing the file? I would prefer it to do this way, because it's easier to automate. Otherwise I'd have to grep config with my script.

Answer 1

Although there is no standard tool to change settings in sshd_config, Ubuntu's post-installation script has some functions for modifying the configuration.

It supports:

• enabling and disabling options
• renaming options
• reading the value of settings, e.g. it retrieves 22 from Port 22
• setting the value of settings, e.g. it can set 22 for Port: Port 22

There are limitations:

• it does not support contexts (like Match)
• it's not aware of the values a key expects, e.g. AllowUsers user@host more@multiple values

It can be found on http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/oneiric/openssh/oneiric/view/head:/debian/openssh-server.postinst

An alternative to such functions using sed. For example, to change a Port setting:

sed "s/^ *Port .*/Port 22/i" -i sshd_config

Obviously, this only works if Port was defined before. As an alternative, you can remove existing settings and append the new setting:

sed "/^ *Port/di" -i sshd_config
echo Port 22 >> sshd_config

Answer 2

As with approximately 99.9999999% of *nix config files, no.

Answer 3

Most applications that provide separate wrappers to edit their config files do so to avoid dangerous race conditions (like the visudo command) or to avoid a syntax error from corrupting the application (again, like what visudo is there for). These things don't really apply to ssh_config.

So the short answer is no. However, that doesn't stop you from making your own.