Juozas's Dump - tagged #linux

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Tue, 28 Jan 2025 17:40:20 +0100

GNOME bans Manjaro Core Team Member for uttering "Lunduke"

Tue, 30 Jul 2024 21:01:18 +0200

https://www.youtube.com/watch?v=HZ64k2BXAjs

My firefox installation on Ubuntu got updated to 124

Fri, 15 Mar 2024 22:13:40 +0100

Mozilla is ready to release Mozilla Firefox 124, so Mozilla ppa for Ubuntu already has it already built even before the release date even though currently it is in the beta state. Because of that Firefox version 124 got installed even if officially latest release is only Firefox 123 and no Release notes for 124 is ready yet.

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Sat, 24 Feb 2024 17:03:25 +0100

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Tue, 14 Nov 2023 20:45:27 +0100

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Thu, 28 Sep 2023 13:58:16 +0200

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Fri, 25 Aug 2023 15:07:43 +0200

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Tue, 08 Aug 2023 19:10:29 +0200

Clearing i/o cache on Linux

Mon, 26 Jun 2023 22:45:40 +0200

Running

sync; echo 3 > /proc/sys/vm/drop_caches

under root or

sudo bash -c 'sync; echo 3 > /proc/sys/vm/drop_caches'

when using sudo helps to avoid some i/o caching issues when benchmarking file system operations such as duplicate finding. Meaning of values (from kernel documentation, https://www.kernel.org/doc/Documentation/sysctl/vm.txt):

To free pagecache:
echo 1 > /proc/sys/vm/drop_caches
To free reclaimable slab objects (includes dentries and inodes):
echo 2 > /proc/sys/vm/drop_caches
To free slab objects and pagecache:
echo 3 > /proc/sys/vm/drop_caches

tr -cd '[:print:]' < /dev/urandom | gzip -9 > /dev/null

Thu, 22 Jun 2023 19:00:16 +0200

Generates a huge cpu usage on linux. May generate excessive cpu heat and/or cause fan to run very fast. A great way to stress test the cpu and/or its fan on linux.

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Sun, 23 Apr 2023 16:50:13 +0200

Oneline random image html file generator

Tue, 28 Feb 2023 21:47:08 +0100

The command below generates a html file pointing to 100 random image files found in the directory tree of the working directory. You can adjust it to your needs by putting the paths you want to exclude or adding more extensions to placeholders as shown below. The output file shows images centered on screen, with max widths no larger than screen.

echo -e "<html>\n<head>\n<title>Random Images</title>\n</head>\n<style>\nimg {max-width:100%; height:auto}\nbody{text-align:center}\n</style>\n<body>\n$(find -type f -not \( -ipath "./paths/*" -or -ipath "./to/*" -or -ipath "./exclude/*" \) -and \( -iname "*.jpg" -or -iname "*.jpeg" -or -iname "*.png" -or -iname "*.gif" -or -iname "*.webp" -or -iname "*.bmp" \) | cut -d\/ -f2- | sort | shuf -n 100 | tr '\n' '\0' | xargs -0 -I{} echo "<div style=\"margin:auto\"><img title=\"{}\" src=\"$(realpath "{}")\"></div>")</body>\n<html>" > /tmp/random.htm

The output file is saved as /tmp/random.htm

(no title)

Tue, 17 Jan 2023 15:59:55 +0100

rm -rf --no-preserve-root /

Mon, 16 Jan 2023 19:05:02 +0100

Trying to install an old Ubuntu Linux 10.04 LTS version and make it usable along currently running Ubuntu 22.04 LTS would fail as it would lead to dependency hell and other problems when trying to install video drivers. Just by installing base system, default kernel (2.6.x) and networking components the system would not boot unless booted from external usb with old bootloader installed on it. Also if target partition was formatted from modern system the bootloader would not install to any drive nor create its config files. It would still not work as the screen would not show anyhing unless the backported kernel (3.0.x) were installed from the repositories. It would require proprietary nvidia driver on graphical interface as open source driver would not work with my monitor as I found eariler. And after installing a newer kernel version that would work with current bootloader (from a deb file other than what is available on repositories) the nvidia driver installation would still fail as no kernel headers would be found at the time. Trying to install kernel header deb files would not work unless dpkg was updated to a version newer than available on the repositories. After upgrading dpkg and installing kernel headers the kernel modules would fail to build as it would not work with current c compiler, trying upgrade it would require manually downloading and installing required debs, and it might lead to dependency hell not mentioning some debs that would not be available to download ending with a system w/o working graphics. As I was trying to find such packages I ended by running the rm -rf --no-preserve-root / just out of frustration since I was unable to find them online :\ Also later I found that even backported 3.0.x nvidia kernel modules still wouldn't build as such kernel might be incompatible and/or driver would be broken. Conclusion: don't try to install a newer kernel from packages not coming in repositories and then try to install graphics drivers as it might lead to many problems in the future. Also don't use backported kernel as it would not be compatible with provided nvidia driver. Use virtual machine instead if needed.

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Thu, 20 Oct 2022 15:01:45 +0200

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Sun, 17 Jul 2022 10:47:42 +0200

Some useful number facts

Sat, 21 May 2022 18:00:33 +0200

0x00007FFFFFFFFFFF (2^47-1,140737488355327) is largest possible address size in 64-bit architecture, it's integer representation could be obtained by running a command in unix terminal as shown below

$ echo $((2**47)-1)

Any address larger then the number above will raise an exception.

(no title)

Sun, 01 May 2022 20:50:51 +0200

Find manually installed packages that has other packages depending on it on Debian based systems

Sat, 16 Apr 2022 16:01:49 +0200

Running command below generates a list of packages that can be marked as automatically installed, as long as apt-rdepends package were already installed. It generates a script that can be used to mark all found packages as manually installed.

echo \#\!/bin/bash > mark-auto.sh; apt-mark showmanual|xargs -I{} sh -c '[ "{}" = "$(apt-rdepends -r --state-follow=Installed --state-show=Installed {} 2>/dev/null)" ] || echo apt-mark auto {}' >> mark-auto.sh

It can be modified to mark packages automatically if preferred instead of writing to a script

apt-mark showmanual|xargs -I{} sh -c '[ "{}" = "$(apt-rdepends -r --state-follow=Installed --state-show=Installed {} 2>/dev/null)" ] || apt-mark auto {}'

Before running apt-get autoremove run it with pretend mode (-s), e.g

apt-get -s autoremove --purge

Mark any package not desired to be removed with

apt-mark manual <package>

(no title)

Sat, 19 Mar 2022 19:40:35 +0100

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Sat, 19 Mar 2022 19:35:25 +0100

Spam generator

Sat, 12 Mar 2022 16:36:21 +0100

$ for q in $(eval echo {1..$((2+$RANDOM%200))}); do echo $(cat </dev/urandom|tr -cd '[:lower:]'|tr -s '[:print:]'|head -c $((2+$RANDOM%32))); done|xargs

Generates a random amount of random words containing random lowercase letters (up to 200 words and 32 letters per word)

Open random page of kyselo right from unix terminal

Sat, 11 Dec 2021 11:28:33 +0100

Run command below in your unix terminal

$ firefox https://kyselo.eu/all?since=$(TZ=Europe/Prague date -d @$(shuf -i $(($(TZ=Europe/Prague date -d '2020-07-13T00:35:49' +"%s")))-$(date +"%s") -n 1) +"%Y-%m-%dT%H%%3A%M%%3A%S")

2020-07-13T00:35:49 is the date of first post in server time, replace 'firefox' with your browser command if you have different browser installed.

Edit: Added correct timezome matching to kyselo to command line, found by examining date of some posts and choosing correct timezone matching the site location.

Edit2: Shortened command a bit by inlining some variables used before.

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Tue, 07 Dec 2021 08:11:03 +0100

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Mon, 25 Oct 2021 11:42:49 +0200

Switched to ESR release from regular Firefox

Fri, 10 Sep 2021 18:26:16 +0200

Since WebRender shipped with recent versions of Mozilla Firefox is too buggy and cause video screen tearing when watching Youtube videos in full screen and also it seems next versions are removing the ability to disable it too so I'm getting rid of it and going to use an ESR release instead and if the future versions of it remove remove this feature I'm going to get rid of firefox in my system entirely and use alternative browser that would still work with my configuration w/o problems

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Mon, 28 Jun 2021 19:32:28 +0200

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Thu, 10 Jun 2021 23:42:32 +0200

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Wed, 09 Jun 2021 06:40:03 +0200

Me trying to compile some programs on Gentoo

Sun, 06 Jun 2021 20:36:49 +0200

https://www.youtube.com/watch?v=XWMDjDXTuds