I’ve been setting up a new Proxmox server and messing around with VMs, and wanted to know what kind of useful commands I’m missing out on. Bonus points for a little explainer.
Journalctl | grep -C 10 'foo' was useful for me when I needed to troubleshoot some fstab mount fuckery on boot. It pipes Journalctl (boot logs) into grep to find ‘foo’, and prints 10 lines before and after each instance of ‘foo’.
The watch command is very useful, for those who don’t know, it starts an automated loop with a default of two seconds and executes whatever commands you place after it.
It allows you to actively monitor systems without having to manually re-run your command.
So for instance, if you wanted to see all storage block devices and monitor what a new storage device shows up as when you plug it in, you could do:
And see in real time the drive mount. Technically not “real time” because the default refresh is 2 seconds, but you can specify shorter or longer intervals.
Obviously my example is kind of silly, but you can combine this with other commands or even whole bash scripts to do some cool stuff.
Ooooh cool, I think this explains how they have our raid monitor set up at work! I keep forgetting to poke through the script
Yeah, it’s a neat little tool. I used it recently at my work. We had a big list of endpoints that we needed to make sure were powered down each night for a week during a patching window.
A sysadmin on my team wrote a script that pinged all of the endpoints in the list and returned only the ones that still were getting a response, that way we could see how many were still powered on after a certain time. But he was just manually running the script every few minutes in his terminal.
I suggested using the watch command to execute the script, and then piping the output into the sort command so the endpoints were nicely alphabetical. Worked like a charm!