Desktop Icons on GNOME

GNOME has traditionally always been one to prefer the benefits of a clean Desktop.

But I'm not one for traditions.

GNOME Extensions

There's an GNOME extention available called Desktop Icons NG (DIN)¹.

If you have installed it, you can see if you properly have it by "gnome-extensions show ding@rastersoft.com".

Once you install it, you can query to see if it is enabled using "gnome-extensions list --enabled", it should contain at least ding@rastersoft.com

Enabling it would probably help: "gnome-extensions enable ding@rastersoft.com" if it's not there.

You're likely to have to logout and log back in, to load extensions.

Extra steps

What I needed to do was:

• copy the application file (thingy.desktop) from /usr/share/applications somewhere and then drag it onto my Desktop.
• Make it Executable
• Set it to "Allow launching"

References

[1] Desktop Icons NG (DING) by rastersoft

https://extensions.gnome.org/extension/2087/desktop-icons-ng-ding/

NFS - Network File System

Network File System (NFS) is used to mount external sources of files between Linux/Unix servers.

Nowadays, I think most people use SAMBA (SMB) as that also allows Windows to join the club, but I decided to try NFS (again).

I used to work with NFS back in the past, but it seems to still be viable.

On the server

We will be sharing the directory /mnt/raid.

I've edited the file /etc/exports.d/raid.exports to contain²:

/mnt/raid 192.168.2.0/24(rw,sync,no_root_squash)

rw

read and write access

sync

is the default, makes certain new requests only get a reply when changes have been committed to stable storage

no_root_squash

By default root files are re-mapped to nobody, to prevent write-access etc. in my case, I wish to edit files using root. I don't mind the security consequences very much in my home situation

To apply changes to this file, run "exportfs -ra" or restart the NFS server.

Start services:

# systemctl start nfs-server.service
# systemctl enable nfs-server.service

Check the status:

  # systemctl status nfs-server.service
● nfs-server.service - NFS server and services
     Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; enabled; preset: disabled)
    Drop-In: /usr/lib/systemd/system/service.d
             └─10-timeout-abort.conf
             /run/systemd/generator/nfs-server.service.d
             └─order-with-mounts.conf
     Active: active (exited) since Sat 2026-08-22 12:50:43 CEST; 1h 14min ago
 Invocation: ee60721a4aa3491b9a6eab2882173531
       Docs: man:rpc.nfsd(8)
             man:exportfs(8)
   Main PID: 2073 (code=exited, status=0/SUCCESS)
   Mem peak: 2.1M
        CPU: 44ms

Aug 22 12:50:43 device-209.home systemd[1]: Starting nfs-server.service - NFS server and services...
Aug 22 12:50:43 device-209.home systemd[1]: Finished nfs-server.service - NFS server and services.

On the client

To view all mountable directories of a certain server, try this:

# mount | grep raid
watson:/mnt/raid on /mnt/raid type nfs4 (rw,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,fatal_neterrors=none,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.2.1,local_lock=none,addr=192.168.2.6)

Or of course try "cat /proc/mounts".

Then, on the client, mount the directory:

# mount -t nfs -o vers=4 watson:/mnt/raid /mnt/raid

Surprisingly, I did not have to actually change any configuration of the NFS service.

Works surprisingly well.

Warning! Ports in Fedora Server are closed by default

If you look at [3], you'll see you have to open up the NFS ports in the firewall configuration:

# firewall-cmd --permanent --add-service=nfs
success
# firewall-cmd --reload
success

Update notice: added a part about reconfiguring the firewall.

References

[1] Fedora Server User Documentation - File sharing with NFS – Installation

https://docs.fedoraproject.org/en-US/fedora-server/services/filesharing-nfs-installation/

[2] My Blog - My Current MDADM Setup

https://randomthoughtsonjavaprogramming.blogspot.com/2024/09/my-current-mdadm-setup.html

[3] Fedora Server User Documentation - File sharing with NFS - Activation

https://docs.fedoraproject.org/en-US/fedora-server/services/filesharing-nfs-installation/#_activation

Converting images to pdf in Linux

Occasionally, I have to scan official papers (dead-tree-copy) and I'd like to keep the result small, and in one pdf.

So, a one liner command would be nice.

magick mrbear*.png -quality 10% -set filename:base "%[basename]" "%[filename:base].jpg"

The commandline above automatically creates an appropriate .jpg file for each mrbear*.png file. So mrbear_0001.png will cause a mrbear_0001.jpg.

Just what I wanted. Went from 8 megabytes picture to a 200 kb picture.

And then converting the new images over to a pdf file is ridiculously simple:

magick mrbear*.jpg mrbear.pdf

Magick!

References

DigitalOcean - Reduce File Size of Images in Linux - CLI and GUI methods

https://www.digitalocean.com/community/tutorials/reduce-file-size-of-images-linux

GitHub - Convert images but keep the original file name #6494

https://github.com/ImageMagick/ImageMagick/discussions/6494

ImageMagick

https://imagemagick.org/

Installing GraalVM on Linux using Alternatives

Was looking for how to install GraalVM on Linux using the Alternatives system.

I've already looked at sdk-man on my MacBook PRO, which works fine.

I found the references below.

References

[1] GraalVM - Installation on Linux Platforms

https://www.graalvm.org/22.3/docs/getting-started/linux/

[2] How to Install GraalVM Community Edition on Linux

https://gist.github.com/ricardozanini/fa65e485251913e1467837b1c5a8ed28

Keyboard problems in Linux with IntelliJ

Numpad arrow keys

So the numpad arrow keys do not work in my IntelliJ editor under Fedora Core 31.

I read about similar issues on the Internet.

One of the solutions that worked for me, was to change the file /usr/share/X11/xkb/symbols/keypad.

First off copying the original file seems like a good idea, something like keypad.original.

Then replace all occurrences of KP_Up, KP_Down, KP_Left, KP_Right with Up, Down, Left, Right respectively.

Either rebooting or executing a setxkbmap should do the trick.

Ctrl-Alt-Left and Ctrl-Alt-Right

I use these to go to the next or previous call in Intellij. Linux just wants to switch Workspaces, when I do that.

The shortcuts could not be found using the standard Settings tool.

But I found a solution at [2].

gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-up []
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-down []
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-left []
gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-right []

With a reset if I decide to need it like:

gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-up
gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-down
gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-left
gsettings reset org.gnome.desktop.wm.keybindings switch-to-workspace-right

References

Medium.com - A simple, humble but comprehensive guide to XKB for linux

https://medium.com/@damko/a-simple-humble-but-comprehensive-guide-to-xkb-for-linux-6f1ad5e13450

[2] Ubuntu - How to disable the keyboard shortcut to switch between workspaces

https://askubuntu.com/questions/744214/how-to-disable-the-keyboard-shortcut-to-switch-between-workspaces

Java Alternatives in Fedora Core - Followup

This is a followup of the blogpost Java Alternatives in Fedora Core.

The instructions in the blogpost also hold for Java 13.

[root@localhost ~]# dnf install java-13-openjdk
[root@localhost ~]# dnf install java-13-openjdk-devel

Unfortunately, there was a snag with Maven, so I thought I'd document it here.

Maven

Maven stubbornly remained firmly pointing to java 8, whatever alternative I picked in my Fedora Core.

[mrbear@localhost ~]$ mvn -version
Apache Maven 3.5.4 (Red Hat 3.5.4-5)
Maven home: /usr/share/maven
Java version: 1.8.0_232, vendor: Oracle Corporation, runtime: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.fc30.x86_64/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.3.11-200.fc30.x86_64", arch: "amd64", family: "unix"

Well, trying to compile a java application with version 13 in the pom.xml, is NOT going to work when your Maven is using openjdk 8.

Really no surprise there.

You get:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project mrbearapp: Fatal error compiling: invalid target release: 13 -> [Help 1]

It turns out I really need to set JAVA_HOME?

Editing .bashrc to add the following:

export JAVA_HOME=/usr/lib/jvm/java-13

Now I get:

[mrbear@localhost ~]$ mvn -version
Apache Maven 3.5.4 (Red Hat 3.5.4-5)
Maven home: /usr/share/maven
Java version: 13.0.1, vendor: N/A, runtime: /usr/lib/jvm/java-13-openjdk-13.0.1.9-2.rolling.fc30.x86_64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.3.11-200.fc30.x86_64", arch: "amd64", family: "unix"

All is as it should be, and we are merrily on our way.

Converting DVD to MP4 using Linux

I recently wished to convert some of my childrens DVDs to MP4, so I could put them on their individual tablets.

I've dabbled with this in the past, on Linux, and it has always been quite a chore to do.

Everything from obscure commandline commands and GUIs that provided a lot of options that were basically meaningless to me (without proper research).

Of course, this caused a lot of grief. Sound not synchronised to the video, or the entirely wrong soundtrack, or converted only the trailers, etc.

But recently I found Handbrake¹, and I was much impressed. A nice gui that only takes a little while to learn, and only for special cases (say for example if you do not wish to have the default English soundtrack).

It has sensible defaults.

The only issue was the installation, as it requires, of course, libcss and all that.

References

[1] Handbrake

https://handbrake.fr/

Adventures in Shell Scripts

A very simple and short blogpost today, sorries.

A colleague decided to automated some simple task by means of a shell script.

This script caused the following error:

rm: cannot remove 'tmp/*': No such file or directory

I quite quickly (after adding -f to defeat the are-you-sure-prompt) found out that double quotes indicated that it should take stuff literally. In this case the script was trying to actually delete the file tmp/*, and not finding it.

The shell did not expand the * properly when encased in double quotes.

A simple example for you to try if this is the case in your environment would be:

echo *

Instead of

echo "*"

Java Alternatives in Fedora Core

Installing Java 11

[root@localhost ~]# dnf install java-11-openjdk
[root@localhost ~]# dnf install java-11-openjdk-devel

Last metadata expiration check: 3:26:53 ago on Mon 12 Nov 2018 09:47:59 AM CET.
Dependencies resolved.
================================================================================
 Package                   Arch       Version                 Repository   Size
================================================================================
Installing:
 java-11-openjdk-devel     x86_64     1:11.0.1.13-1.fc28      updates     3.4 M

Transaction Summary
================================================================================
Install  1 Package

Total download size: 3.4 M
Installed size: 5.1 M
Is this ok [y/N]: y
Downloading Packages:
java-11-openjdk-devel-11.0.1.13-1.fc28.x86_64.rpm                                                                                                                                                75 kB/s | 3.4 MB     00:45
----------------------------------------------------------------------------------
Total                                                     72 kB/s | 3.4 MB     00:47
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing                                       1/1
  Installing       : java-11-openjdk-devel-1:11.0.1.13-1.fc28.x86_64                                        1/1 
  Running scriptlet: java-11-openjdk-devel-1:11.0.1.13-1.fc28.x86_64                                        1/1 
                                               1/1 
  Verifying        : java-11-openjdk-devel-1:11.0.1.13-1.fc28.x86_64                                                         1/1 

Installed:
  java-11-openjdk-devel.x86_64 1:11.0.1.13-1.fc28                                                               

Complete!

Switching to another Java version

[mrbear@localhost ~]$ sudo alternatives --config java
[mrbear@localhost ~]$ sudo alternatives --config javac

There are 2 programs which provide 'javac'.

  Selection    Command
-----------------------------------------------
*  1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.181.b15-6.fc28.x86_64/bin/javac)
 + 2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.1.13-1.fc28.x86_64/bin/javac)

Enter to keep the current selection[+], or type selection number:

Of course my IntelliJ automatically detects the different Java versions installed on the system, when I tell it to add a new version of Java.

Nice.

References

Using alternative utils with JRE & JDK

https://robbinespu.github.io/eng/2018/03/21/Updating_java_with_alternative.html

Superhero Ninja - Easily switch between java versions using alternatives in Linux

https://superhero.ninja/2015/02/07/easily-switch-between-java-versions-using-alternatives-in-linux/

Excluding packages in DNF

In the file /etc/dnf/dnf.conf, you can enter which packages need to be excluded.

I like to exclude java packages, until I am ready for them (as they require a reboot of my application server):

[main]
gpgcheck=1
installonly_limit=3
clean_requirements_on_remove=true
exclude=java*

Or for instance:

[main]
gpgcheck=1
installonly_limit=3
clean_requirements_on_remove=true
exclude=kernel* java*

When I am ready to install all packages, regardless of excludes, I can use the commandline below.

$ dnf -y update --disableexcludes=all

References

Fedora 24: Exclude package from update

https://www.hiroom2.com/2016/07/07/fedora-24-exclude-package-from-update/

SysTutorials - Making dnf/yum Not Update Certain Packages

https://www.systutorials.com/1661/making-dnf-yum-not-update-certain-packages/

Problems with Resolution and My Monitor in Fedora Core 25

Well, my monitor always has been a bit of a problem child, but it worked, so I didn't mind.

I let it bounce once on the floor, but besides some slight discolouring in the lower-right corner, it was fine.

It reports EDID settings that are completely crap, but I got used to ignoring those, using xrandr.

XRandr settings that work for me

The following settings work:

xrandr --newmode "1920x1440" 339.50  1920 2072 2280 2640  1440 1443 1447 1514 -
xrandr --addmode VGA-0 1920x1440
xrandr --newmode "1600x1200" 235.00  1600 1728 1896 2192  1200 1203 1207 1262 -
xrandr --addmode VGA-0 1600x1200
xrandr --newmode "1280x1024"  159.50  1280 1376 1512 1744  1024 1027 1034 1078
xrandr --addmode VGA-0 1280x1024
xrandr --output VGA-0 --mode 1920x1440

Problem

Then I upgraded to Fedora Core 25, and my monitor showed me a handsome 1024x768, which was a disappointment to say the least. (I'm used to 1920x1440.)

Using xrandr gave me the cryptic error message:

bash-4.3$ xrandr --output XWAYLAND0 --mode "1920x1440"
xrandr: Configure crtc 0 failed

After some research I noticed that Fedora Core 25 is the first one to use Wayland¹ as the default.

Solution

Switching back to the old Xorg² fixed my problem.

Checking graphics card

bash-4.3$  lspci -nnk |grep -A 3 -i vga
01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Juniper XT [Radeon HD 5770] [1002:68b8]
        Subsystem: ASUSTeK Computer Inc. Device [1043:0344]
        Kernel driver in use: radeon
        Kernel modules: radeon

References

[1] Wayland Desktop

https://wayland.freedesktop.org/

[2] Fedora Project - Switching back to Xorg

https://fedoraproject.org/wiki/Changes/WaylandByDefault

Fedoraforum.org - how to install amd/ati driver on fedora 25?

http://forums.fedoraforum.org/showthread.php?t=312919

AskFedora - How to add a custom resolution to Weyland Fedora 25?

https://ask.fedoraproject.org/en/question/99867/how-to-add-a-custom-resolution-to-weyland-fedora-25/

ArchLinux - Forcing modes and EDID

https://wiki.archlinux.org/index.php/Kernel_mode_setting#Forcing_modes_and_EDID

Bugzilla Redhat - My Bugreport

https://bugzilla.redhat.com/show_bug.cgi?id=1443761

More, Less and Most

I found the following gem in [1]:

“less is more, but more more than more is, so more is less less, so use more less if you want less more.”

— Joost Kremers²

“If less is more than more, most is more than less.”

— Slackware Linux Essentials²

References

[1] Stackoverflow - What are the differences between most, more and less?

http://unix.stackexchange.com/questions/81129/what-are-the-differences-between-most-more-and-less

[2] Slackware Linux Essentials - 10.2 Pagers: more, less, and most

http://www.slackbook.org/html/file-commands-pagers.html