I’m an old Unix/Linux guy who has been away from modern Linux distros for a while. And I’ve simply found myself absolutely bewildered after ssh’ing into my BBB.
I simply need a pointer to where I can find information about command line system admin for this sort of Linux distribution. As an analogy, I found that for my Raspberry Pi running Raspbian, I could read about Debian admin and package management. What should I be looking toward to understand Angstrom (command-line) system administration.
A specific question is where can I find more about systemctl? As an example, I would like to know how sshd is started on my BBB (It runs just fine). But I can’t find an sshd.service file as the man pages would lead me to believe exists. Nor do I find a “traditional” init.d file. (It was /etc/init.d/README that told me to learn about systemctl.) And I even desperately looked under xinitd.d.
I feel like there must be some trove of documentation that I’m failing to find. I have looked before posting here.
I can always put some OS I’m more familiar with on a microSD, but I would like to give Angstrom a fair chance first.
Cheers,
-j
This should be of help to you. The amazing Arch wiki's to the rescue.
This is just the starting point, it will link you to just about
everything you want to know.
https://wiki.archlinux.org/index.php/systemd
I think learning systemd is worthwhile, as it is a much more powerful system than sysvinit. It’s also the default init for Fedora, Arch, and several other big distros. Ubuntu uses an alternate init system called Upstart that is also more powerful and flexible than sysvinit. Both allow you to explicitly model the actual dependencies between services that run, so everything gets initialized in order but as quickly as possible. Upstart and systemd can both significantly cut down on boot time, but systemd goes even further by also taking on the role of inetd, which will open sockets on the ports that services will use in anticipation of starting the service, and hand the sockets over when the service is finished starting. You can use this to trigger the starting of services as well.
For example, if you’re tight on resources, you can have systemd listen on port 22 in place of a ssh daemon. It won’t actually start the daemon until someone connects to the port, though. And if you have a service you’ve written that requires other resources to run, it will ensure your service will start as soon as those are available. I’ve spent a lot of time pulling my hair out trying to resolve nondeterministic startup issues in a systemvinit-based embedded system.
ps -e | grep ssh
gives ssh-agent
cd /etc
grep -R ssh *
=>
gdm/Xsession
My cloud9-gnome-image has dropbear which provides ssh