Technology Tales

Adventures & experiences in contemporary technology

Controlling display of users on the logon screen in Linux Mint 20.3

15th February 2022

Recently, I tried using Commento with a static website that I was developing and this needed PostgreSQL rather than MySQL or MariaDB, which many content management tools use. That meant a learning curve that made me buy a book as well as the creation of a system account for administering PostgreSQL. These are not the kind of things that you want to be too visible so I wanted to hide them.

Since Linux Mint uses AccountsService, you cannot use lightdm to do this (the comments in /etc/lightdm/users.conf suggest as much). Instead, you need to go to /var/lib/AccountsService/users and look for a file called after the user name. If one exists, all that is needed is for you to add the following line under the [User] section:

SystemAccount=true

If there is no file present for the user in question, then you need to create one with the following lines in there:

[User]
SystemAccount=true

Once the configuration files are set up as needed, AccountsService needs to be restarted and the following command does that deed:

sudo systemctl restart accounts-daemon.service

Logging out should reveal that the user in question is not listed on the logon screen as required.

Getting rid of the Windows Resizing message from a Manjaro VirtualBox guest

27th July 2020

Like Fedora, Manjaro also installs a package for VirtualBox Guest Additions when you install the Linux distro in a VirtualBox virtual machine. However, it does have certain expectations when doing this. On many systems and my own is one of these, Linux guests are forced to use the VMSVGA virtual graphics controller while Windows guests are allowed to use the VBoxSVGA one. It is the latter that Manjaro expects so you get a message like the following appearing when the desktop environment has loaded:

Windows Resizing
Set your VirtualBox Graphics Controller to enable windows resizing

After ensuring that gcc, make, perl and kernel headers are installed, I usually install VirtualBox Guest Additions myself from the included ISO image and so I did the same with Manjaro. Doing that and restarting the virtual machine got me extra functionality like screen resizing and being able to copy and paste between the VM and elsewhere after choosing the Bidirectional setting in the menus under Devices > Shared Clipboard.

That still left an unwanted message popping up on startup. To get rid of that, I just needed to remove /etc/xdg/autostart/mhwd-vmsvga-alert.desktop. It can be deleted but I just moved it somewhere else and a restart proved that the message was gone as needed. Now everything is working as I wanted.

Restoring the menu bar on GNOME Terminal in a GNOME Shell session

25th July 2020

By default, a GNOME Terminal instance does not display a menu bar and that applies not only in GNOME Shell but also on the Cinnamon Desktop environment. In the latter, it is easy enough to display the menu bar using the context menu produced by right clicking in the window before going to Edit > Preferences and ticking the box for Show menubar by default in new terminals in the General section. After closing the Preferences dialogue, every new GNOME Terminal session will show the menu bar.

Unfortunately, it is not so easy in GNOME Shell though the context menu route does allow you to unhide the menu bar on a temporary basis. That is because the requisite tickbox is missing from the Preferences dialogue box displayed after navigating to Edit > Preferences in the menus. To address, you need the execute the following command in a terminal session:

gsettings set org.gnome.Terminal.Legacy.Settings headerbar false

This not only adds the menu bar on a permanent basis but it also adds the missing tickbox, populated as required. GNOME Shell may be minimalist in some ways but making this action harder looks like going a little too far.

Creating a VirtualBox virtual disk image using the Linux command line

9th September 2019

Much of the past weekend was spent getting a working Debian 10 installation up and running in a VirtualBox virtual machine. Because I chose the Cinnamon desktop environment, the process was not as smooth as I would have liked so a minimal installation was performed before I started to embellish as I liked. Along the way, I got to wondering if I could create virtual hard drives using the command line and I found that something like the following did what was needed:

VBoxManage createmedium disk --filename <full path including file name without extension> -size <size in MiB> --format VDI --variant Standard

Most of the options are self-explanatory part from the one named variant. This defines whether the VDI file expands to the maximum size specified using the size parameter or is reserved with the size defined in that parameter. Two VDI files were created in this way and I used these to replace their Debian 8 predecessors and even to save a bit of space too. If you want, you can find out more in the user documentation but this post hopefully gets you started anyway.

Installing Firefox Developer Edition in Linux Mint

22nd April 2018

Having moved beyond the slow response and larger memory footprint of Firefox ESR, I am using Firefox Developer Edition in its place even if it means living without a status bar at the bottom of the window. Hopefully, someone will create an equivalent of the old add-on bar extensions that worked before the release of Firefox Quantum.

Firefox Developer Edition may be pre-release software with some extras for web developers like being able to to drill into an HTML element and see its properties but I am finding it stable enough for everyday use. It is speedy too, which helps, and it has its own profile so it can co-exist on the same machine as regular releases of Firefox like its ESR and Quantum variants.

Installation takes a little added effort though and there are various options available. My chosen method involved Ubuntu Make. Installing this involves setting up a new PPA as the first step and the following commands added the software to my system:

sudo add-apt-repository ppa:ubuntu-desktop/ubuntu-make
sudo apt-get update
sudo apt-get install ubuntu-make

With the above completed, it was simple to install Firefox Developer edition using the following command:

umake web firefox-dev

Where things got a bit more complicated was getting entries added to the Cinnamon Menu and Docky. The former was sorted using the cinnamon-menu-editor command but the latter needed some tinkering with my firefox-developer.desktop file found in .local/share/applications/ within my user area to get the right icon shown. Discovering this took me into .gconf/apps/docky-2/Docky/Interface/DockPreferences/%gconf.xml where I found the location of the firefox-developer.desktop that needed changing. Once this was completed, there was nothing else to do from the operating system side.

Within Firefox itself, I opted to turn off warnings about password logins on non-https websites by going to about:config using the address bar, then looking for security.insecure_field_warning.contextual.enabled and changing its value from True to False. Some may decry this but there are some local websites on my machine that need attention at times. Otherwise, Firefox is installed with user access so I can update it as if it were a Windows or MacOS application and that is useful given that there are frequent new releases. All is going as I want it so far.

Dropping back to a full screen terminal session from a desktop one in Linux

29th May 2014

There are times when you might need to drop back to a full screen terminal session from a graphical desktop environment when running Linux. One example that I have encountered is the installation of Nvidia’s own graphics drivers on either Ubuntu or Linux Mint. Another happened to me on Arch Linux when a Cinnamon desktop environment update left me without the ability to open up a terminal window. Then, the full screen command allowed me to add in an alternative terminal emulator and Tech Drive-in’s list came in handy for this. there might have been something to sort on a FreeBSD installation that needed the same treatment. This latter pair happened to me on sessions running within VirtualBox and that has its own needs when it comes to dropping into a full screen command line session and I will come to that later.

When running Linux on a physical PC, the keyboard shortcuts that you are CTRL + ALT + F1 for entering a full screen terminal session and CTRL + ALT + F7 for returning to the graphical desktop again. When you are running a Linux guest in VirtualBox and the host operating system also is Linux, then the aforementioned shortcuts do not work within the virtual machine but instead affect the host. To get the guest operating system to drop into a full screen terminal session, the keyboard shortcut you need is [Host Key] + F1 and the default host key is the right hand CTRL key on your keyboard unless you have assigned to something else as I have. The exit the full screen terminal session and return to the graphical desktop again, the keyboard shortcut is [Host Key] + F7.

All of this works with GNOME and Cinnamon desktop environments running in X sessions and I cannot vouch for anything else unless alternatives like Wayland come my way. Hopefully, this useful functionality applies to those other set-ups too because there are times when a terminal session is needed to recover from a mishap, rare though those thankfully are and they need to be very rare if not non-existent for most users.

Fixing Background Image Display in GNOME Shell 3.10

2nd May 2014

On upgrading from Ubuntu GNOME 13.10 to Ubuntu GNOME 14.04, a few rough edges were to be noticed. One was the display of my chosen background image: it was garbled. Later, I discovered that there is a maximum width of 2560 px for background images in GNOME Shell these days and that things get messy beyond that.

In my case, the image width was around 6000 px and I was used to its getting resized in GNOME Shell 3.8 and its predecessors. It seems that the functionality got removed after that though so the workaround of manual image resizing in the GIMP needed to be employed. Though having big images open in memory creates an additional overhead, not handling them very well at all looks like a bug caused by setting 2560 px as a maximum screen width for the GNOME Shell panel and the complete removal of Nautilus from desktop rendering duties. Let’s hope that sense is seen with ever larger screen sizes and resolutions coming our way.

It’s the sort of thing that did get me looking at adding on Cinnamon 2.2 for a while before setting background image scaling using the indispensable GNOME Tweak Tool was discovered. LinuxG.net has a useful tutorial on this for anyone with such an adventurous streak in them. For now though, I am OK with my set up but the GNOME project’s focus on minimalism could affect us in other ways so I can see why Clem Lefebvre started the Cinnamon one primarily for Linux Mint and the desktop environment is appearing elsewhere too. After all, Gedit lost its menu bar in GNOME 3.12 so it’s just as well that we have alternative choices.

Update 2014-05-06: It seems that the desktop image bug that afflicts GNOME Shell 3.10 got sorted for GNOME Shell 3.12. At least, that is the impression that an Antergos instance in a VirtualBox virtual machine gives me.

Installing FreeBSD in a VirtualBox Virtual Machine

2nd March 2014

With UNIX being the basis of Linux, I have a soft spot for trying out any UNIX that can be installed on a PC. For a while, I had OpenSolaris on the go and even vaguely recall having a look at one of the BSD’s. However, any recent attempt to install one of the latter, and there are quite a few around now, got stymied by some sort of kernel panic caused by using AMD CPU’s. With the return to the Intel fold arising from the upgrade of my main home PC last year, it perhaps was time to try again.

The recent release of FreeBSD 10.0 was the cue and I downloaded a DVD image for a test installation in a VirtualBox virtual machine with 4 GB of memory and a 32 GB virtual hard drive attached (expanding storage was chosen so not all the allocated space has been taken so far). The variant of FreeBSD chosen was the 64-bit x86 one and I set to installing it in there. Though not as pretty in appearance as those in various Linux distros, the installer was not that user unfriendly to me. Mind you, I have experience of installing Arch Linux so that might have acclimatised me somewhat.

Those installation screens ask about the keyboard mapping that you want and I successfully chose one of the UK options. There was limited opportunity for adding extras though there was a short list of few from which I made some selections. User account set up also was on offer and I would have been better off knowing what groups to assign for my personal user account so as to have to avoid needing to log in as root so often following system start up later. Otherwise, all the default options were sufficient.

When the installation process was complete, it was time to boot into the new system and all that was on offer was a command line log in session. After logging in as root, it was time to press pkg into service in order to get a desktop environment in place. The first step was to install X:

pkg install xorg

Then, it was time to install a desktop environment. While using XFCE or KDE were alternatives, I chose GNOME 2 due to familiarity and more extensive instructions on the corresponding FreeBSD handbook page. Issuing the following command added GNOME and all its helper applications:

pkg install gnome2

So that GNOME starts up at the next reboot, some extra steps are needed. The first of these is to add the following line into /etc/fstab:

proc /proc procfs rw 0 0

Then, two lines were needed in /etc/rc.conf:

gdm_enable=”YES”
gnome_enable=”YES”

The first enables the GNOME display manager and the second activates other GNOME programs that are needed for a desktop session to start. With each of these in place, I got a graphical login screen at the next boot time.

With FreeDSB being a VirtualBox Guest, it was time to consult the relevant FreeBSD manual page. Here, there are sections for a number of virtual machine tools so a search was needed to find the one for VirtualBox. VirtualBox support for FreeBSD is incomplete in that there is no installation media for BSD systems though Linux and Solaris are supported along with Windows. Therefore, it is over to the FreeBSD repositories for the required software:

pkg install virtualbox-ose-additions

Aside from the virtual machine session not capturing and releasing the mouse pointer automatically, that did everything that was needed even if it was the open source edition of the drivers and their proprietary equivalents. To resolve the mouse pointer issue, I needed to temporarily disable the GNOME desktop session in /etc/rc.conf to drop down to a console only session where xorg. conf could be generated using the following commands:

Xorg -configure
cp xorg.conf.new /etc/xorg.conf

In the new xorg.conf file, the mouse section needs to be as follows:

Section “InputDevice”
Identifier  “Mouse0”
Driver      “vboxmouse”
EndSection

If it doesn’t look like the above and it wasn’t the case for me then it needs changing. Also, any extra lines from the default set up also need removing or the mouse will not function as it should. The ALT+F1 (for accessing GNOME menus) and ALT+F2 (for running commands) keyboard shortcuts then become crucial when your mouse is not working as it should and could avert a panic too; knowing that adjusting a single configuration file will fix a problem when doing so is less accessible is not a good feeling as I discovered to my own cost. The graphics settings were fine by default but here’s what you should have in case it isn’t for you:

Section “Device”
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: “True”/”False”,
### <string>: “String”, <freq>: “<f> Hz/kHz/MHz”
### [arg]: arg optional
Identifier  “Card0”
Driver      “vboxvideo”
VendorName  “InnoTek Systemberatung GmbH”
BoardName   “VirtualBox Graphics Adapter”
BusID       “PCI:0:2:0”
EndSection

The next step is to ensure that your HAL settings are as they should. I needed to create a file in /usr/local/etc/hal/fdi/policy called 90-vboxguest.fdi that contains the following:

<?xml version=”1.0″ encoding=”utf-8″?>
<!--
# Sun VirtualBox
# Hal driver description for the vboxmouse driver
# $Id: chapter.xml,v 1.33 2012-03-17 04:53:52 eadler Exp $
Copyright (C) 2008-2009 Sun Microsystems, Inc.
This file is part of VirtualBox Open Source Edition (OSE, as
available from http://www.virtualbox.org. This file is free software;
you can redistribute it and/or modify it under the terms of the GNU
General Public License (GPL) as published by the Free Software
Foundation, in version 2 as it comes in the “COPYING” file of the
VirtualBox OSE distribution. VirtualBox OSE is distributed in the
hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
Clara, CA 95054 USA or visit http://www.sun.com if you need
additional information or have any questions.
-->
<deviceinfo version=”0.2″>
<device>
<match key=”info.subsystem” string=”pci”>
<match key=”info.product” string=”VirtualBox guest Service”>
<append key=”info.capabilities” type=”strlist”>input</append>
<append key=”info.capabilities” type=”strlist”>input.mouse</append>
<merge key=”input.x11_driver” type=”string”>vboxmouse</merge>
<merge key=”input.device” type=”string”>/dev/vboxguest</merge>
</match>
</match>
</device>
</deviceinfo>

With all that set, it is time to ensure that the custom user account is added to the wheel and operator groups using this command:

pw user mod [user name] -G wheel operator

Executing the above as root means that the custom account can run the su command so that logging in as root at the start of a desktop session no longer is needed. That is what being in the wheel group allows and the anyone in the operator group can shut down or restart the system. Both are facilities readily available in Linux so I fancied having them in FreeBSD too.

Being able to switch to root in a terminal session meant that I could go on to add software like Firefox, Libreoffice, GIMP, EMACS, Geany, Netbeans, Banshee and so on. There may be a line of opinion that FreeBSD is a server operating system but all of these make it more than passable for serving as a desktop one too. There may be no package management GUI as such and the ones that come with GNOME do not work either but anyone familiar with command line working will get around that.

FreeBSD may be conservative but that has its place too and being able to build up a system one item at a time teaches far more than getting everything already sorted in one hit. So far, there is enough documentation to get me going and I hope to see where else things go too. So far, the OS hasn’t been that intimidating and that’s good to see.

A fallback method of installing Nightingale in Linux

3rd December 2013

When I upgraded to Ubuntu GNOME 13.10 and went for the 64-bit variant, I tried a previously tried and tested approach for installing Nightingale that used a PPA only for it not to work. At that point, the repository had not caught up with the latest Ubuntu release (it has by the time of writing) and other pre-compiled packages would not work either. However, there was one further possibility left and that was downloading a copy of the source code and compiling that. My previous experiences of doing that kind of thing have not been universally positive so it was not my first choice but I gave it a go anyway.

In order to get the source code, I first needed to install Git so I could take a copy from the version controlled repository and the following command added the tool and all its dependencies:

sudo apt-get install git autoconf g++ libgtk2.0-dev libdbus-glib-1-dev libtag1-dev libgstreamer-plugins-base0.10-dev zip unzip

With that lot installed, it was time to checkout a copy of the latest source code and I went with the following:

git clone https://github.com/nightingale-media-player/nightingale-hacking.git

The next step was to go into the nightingale-hacking sub-folder and issue the following command:

./build.sh

That should produce a sub-directory named nightingale that contains the compiled executable files. If this exists, it can be copied into /opt. If not, then create a folder named nightingale under /opt using copy the files from ~/nightingale-hacking/compiled/dist into that location. Ubuntu GNOME 13.10 comes with GNOME Shell 3.8, the next step took a little fiddling before it was sorted: adding an icon to application menu or dashboard. This involved adding a file called nightingale.desktop in /usr/share/applications/ with the following contents:

[Desktop Entry]
Name=Nightingale
Comment=Play music
TryExec=/opt/nightingale/nightingale
Exec=/opt/nightingale/nightingale
Icon=/usr/share/pixmaps/nightingale.xpm
Type=Application
X-GNOME-DocPath=nightingale/index.html
X-GNOME-Bugzilla-Bugzilla=Nightingale
X-GNOME-Bugzilla-Product=nightingale
X-GNOME-Bugzilla-Component=BugBuddyBugs
X-GNOME-Bugzilla-Version=1.1.2
Categories=GNOME;Audio;Music;Player;AudioVideo;
StartupNotify=true
OnlyShowIn=GNOME;Unity;
Keywords=Run;
Actions=New
X-Ubuntu-Gettext-Domain=nightingale

[Desktop Action New]
Name=Nightingale
Exec=/opt/nightingale/nightingale
OnlyShowIn=Unity

It was created from a copy of another *.desktop file and the categories in there together with the link to the icon were as important as the title and took a little tinkering before all was in place.  Also, you may find that /opt/nightingale/chrome/icons/default/default.xpm needs to be become /usr/share/pixmaps/nightingale.xpm using the cp command before your new menu entry gains an icon to go with it. While the steps that I describe here worked for me, there is more information on the Nightingale wiki if you need it.

Setting up a WD My Book Live NAS on Ubuntu GNOME 13.10

1st December 2013

The official line from Western Digital is that they do not support the use of their My Book Live NAS drives with Linux or UNIX. However, what that means is that they only develop tools for accessing their products for Windows and maybe OS X. It still doesn’t mean that you cannot access the drive’s configuration settings by pointing your web browser at http://mybooklive.local/. In fact, not having those extra tools is no drawback at all since the drive can be accessed through your file manager of choice under the Network section and the default name is MyBookLive too so you easily can find the thing once it is connected to a router or switch anyway.

Once you are in the servers web configuration area, you can do things like changing its name, updating its firmware, finding out what network has been assigned to it, creating and deleting file shares, password protecting file shares and other things. These are the kinds of things that come in handy if you are going to have a more permanent connection to the NAS from a PC that runs Linux. The steps that I describe have worked on Ubuntu 12.04 and 13.10 with the GNOME  desktop environment.

What I was surprised to discover that you cannot just set up a symbolic link that points to a file share. Instead, it needs to be mounted and this can be done from the command line using mount or at start-up with /etc/fstab. For this to happen, you need the Common Internet File System utilities and these are added as follows if you need them (check on the Software Software or in Synaptic):

sudo apt-get install cifs-utils

Once these are added, you can add a line like the following to /etc/fstab:

//[NAS IP address]/[file share name] /[file system mount point] cifs
credentials=[full file location]/.creds,
iocharset=utf8,
sec=ntlm,
gid=1000,
uid=1000,
file_mode=0775,
dir_mode=0775
0 0

Though I have broken it over several lines above, this is one unwrapped line in /etc/fstab with all the fields in square brackets populated for your system and with no brackets around these. Though there are other ways to specify the server, using its IP address is what has given me the most success and this is found under Settings > Network on the web console. Next up is the actual file share name on the NAS and I have used a custom them instead of the default of Public. The NAS file share needs to be mounted to an actual directory in your file system like /media/nas or whatever you like and you will need to create this beforehand. After that, you have to specify the file system and it is cifs instead of more conventional alternatives like ext4 or swap. After this and before the final two space delimited zeroes in the line comes the chunk that deals with the security of the mount point.

What I have done in my case is to have a password protected file share and the user ID and password have been placed in a file in my home area with only the owner having read and write permissions for it (600 in chmod-speak). Preceding the filename with a “.” also affords extra invisibility. That file then is populated with the user ID and password like the following. Of course, the bracketed values have to be replaced with what you have in your case.

username=[NAS file share user ID]
password=[NAS file share password]

With the credentials file created, its options have to be set. First, there is the character set of the file (usually UTF-8 and I got error code 79 when I mistyped this) and the security that is to be applied to the credentials (ntlm in this case). To save having no write access to the mounted file share, the uid and gid for your user needs specification with 1000 being the values for the first non-root user created on a Linux system. After that, it does no harm to set the file and directory permissions because they only can be set at mount time; using chmod, chown and chgrp later on has no effect whatsoever. Here, I have set permissions to read, write and execute for the owner and the user group while only allowing read and execute access for everyone else (that’s 775 in the world of chmod).

All of what I have described here worked for me and had to gleaned from disparate sources like Mount Windows Shares Permanently from the Ubuntu Wiki, another blog entry regarding the permissions settings for a CIFS mount point and an Ubuntu forum posting on mounting CIFS with UTF-8 support. Because of the scattering of information, I just felt that it needed to all together in one place for others to use and I hope that fulfils someone else’s needs in a similar way to mine.

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