A QUICK REFERENCE TO… DMESG
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When you boot your favourite Linux distro, you probably see a pretty splash screen. That’s Linux doing an impression of a swan: calm and serene on top but all sorts going on underneath.
We’d love to try and answer any questions you send to lxf.answers@futurenet.com, no matter what the level. We’ve all been stuck before, so don’t be shy. However, we’re only human (although many suspect Jonni is a robot), so it’s important that you include as much information as you can. If something works on one distro but not another, then tell us. If you get an error message, please tell us the exact message and precisely what you did to invoke it.
Q
Space invaders
My 1TB SSD is at 37 per cent full. It seems to be more full than expected. Is there a GUI program, or command line for terminal, that I can use to see the size(s) of files listed, instead of having to check the size of each folder individually with the mouse?
If you boot without the splash screen you’ll see a lot of text flying by. The first part is the kernel setting itself up, recognising hardware and loading drivers. This flies past and you usually don’t need to see it, but what if something doesn’t work right and you want this information? The kernel keeps a ring buffer –a buffer of fixed size – that keeps the most recent messages. You can view this with the dmesg command, which you would normally view through a pager: $ dmesg | less Most of the time you won’t need this, but it’s useful if you have a piece of hardware that doesn’t work properly. For example, some devices need a firmware file as well as a driver, which is usually loaded from lib/firmware, so you can check this with $ dmesg | grep firmware
If you have, or suspect, a hardware problem, let us know about the hardware. Consider installing hardinfoor lshw. These programs list the hardware on your machine, so send us their output. If you’re unwilling, or unable, to install these, run the following commands in a root terminal and send us the system.txt file too. uname -a > system.txt lspci >> system.txt lspci -vv >> system.txt
The only program that I can think of that may be taking up a lot of space is my
Thunderbird
mail, as it saves/ archives many years’ worth of emails. However, upon checking the invisible folder .thunderbird, it’s only 3.5GB Perhaps there’s another folder that Thunderbird saves all the past emails in?
If you’re trying to sort out hotplugged hardware, dmesg has a useful --follow option that shows new messages as they are generated by the kernel. For example, running this command: $ dmesg --follow | grep -e sd -e usb and then plugging in a USB drive will display information about the drive as it happens.