• 18 Posts
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Cake day: July 24th, 2023

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  • unlawfulboogertolinuxmemes@lemmy.world🐧> 🪟
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    1 month ago

    Well yes, assuming that:

    1. you trust the hardware manufacturer
    2. you can install your own keys (i.e. not locked by vendor)
    3. you secure your bios with a secure password
    4. you disable usb / network boot

    With this you can make your laptop very tamper resistant. It will be basically impossible to tamper with the bootloader while the laptop is off. (e.g install keylogger to get disk-encryption password).

    What they can do, is wipe the bios, which will remove your custom keys and will not boot your computer with secure boot enabled.

    Something like a supply-side attack is still possible however. (e.g. tricking you into installing a malicious bootloader while the PC is booted)

    Always use security in multiple layers, and to think about what you are securing yourself from.





  • I get it, sometimes you just do something for the challenge.

    It’s really great what you can accomplish when you know a little more than the bare minimum of the tools at your disposal (^^,)

    And I had the same experience after learning a bit more about awk for the fist time, hahaha.


  • unlawfulboogertoLinux@lemmy.mlJackett memory leak
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    4 months ago

    Virtual memory is different from swap memory.

    Swap memory is used when you run out of physical memory, so the memory is extended to your storage.

    Virtual memory is an abstraction that lies between programs using memory and the physical memory in the device. It can be something like compression and memory-mapped files, like mentioned.

    And yes, some swap is still useful, up to something like 4G for larger systems.

    And if you want to hibernate to disk, you may need as much swap as your physical memory. But maybe that’s changed. I haven’t done that in years.





  • In the end I’ve used the first command you wrote, because KISS, but I appreciate your explanation

    There’s no shame in combining multiple tools, that’s what pipelines are all about 😄.

    Also there’s a different tool that I would use if I want to output a specific column: awk

    df -h —output=avail,source | awk ‘/\/dev\/dm-2/ {print $1}’
    

    For lines matching /dev/dm-2 print the first column. awk splits columns on whitespace by default.

    But I would probably use grep+awk.

    Sed is definitely a very powerful tool, which leads to complex documentation. But I really like the filtering options before using the search/replace.

    You can select specific lines, with regex or by using a line number; or you can select multiple lines by using a comma to specify a range.

    E.g. /mystring/,100s/input/output/g: in the lines starting from the first match of /mystring/ until line 100, replace input with output


  • unlawfulboogertoLinux@lemmy.mlHelp with sed commands
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    4 months ago

    The easiest way is probably without sed, which you mentioned:

    df -h --output=avail /dev/dm-2| tail -n1
    

    But purely with sed it would be something like this:

    df -h --output=avail,source | sed -n ‘/\/dev\/dm-2/s!/dev/dm-2!!p’
    

    -n tells sed to not print lines by default

    /[regex]/ selects the likes matching regex. We need to escape the slashes inside the regex.

    s/// does search-and-replace, and has a special feature: it can use any character, not just a slash. So I used three exclamation points instead , so that I don’t need to escape the slashes. Here we replace the device with the empty string.

    p prints the result

    Check the sed man page for more details: https://linux.die.net/man/1/sed