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(upbeat music)

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- [Instructor] Let's look at

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my solutions for those challenges.

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So, hopefully you found in proc

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a file called command line

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with a little bit abbreviated spelling.

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If we cat that out, that's what was passed

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by the boot loader to the kernel at boot time.

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Alright, now let's use demesg

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and see if we can find that,

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and we'll grep for BOOT_IMAGE,

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since that's what it started with.

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And there we see it.

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Also, notice we've got this message here.

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"Unknown kernel command line parameters,"

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"will be passed to user space."

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This is kind of good to know.

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You can put almost anything you want

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on the kernel command line.

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If the kernel doesn't know what it is, then it's ignored.

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But it's still there,

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and utilities can look at like,

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proc command line for extra options.

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Like here, it's documenting which kernel was booted.

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Might be helpful to know about the command line.

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And we also said,

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hey, is the kernel command line

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stored in a log file somewhere?

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So let's do a recursive grep

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for BOOT_IMAGE= underneath /var/log,

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and you get lots of hits.

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So there's a syslog, there's a dmesg log, and so forth.

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So that's a place to look.

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What about with journalctl?

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Journalctl -k |grep BOOT_IMAGE=.

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It's there, too.

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Okay, I notice we get the warning there, and so forth.

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And then we had another challenge question.

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How much memory, how much RAM do you have on your system?

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Well if you look at /proc/meminfo,

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at the top there, MemTotal.

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So, looks like 16 gig on this system.