Technology Tales

Getting rid of the "Get more security upgrades through Ubuntu Pro with 'esm-apps' enabled" message when performing a system update

Not so long ago, I got the above message while running sudo apt upgrade on an Ubuntu Server system. This was not the first time that this kind of thing happened to me, so I started searching the web for a solution. You do get to see complaints about advertising, but these are never useful.

Accordingly, here are some possible ways of remediating the situation:

• Execute the following commands to disable the responsible services, renaming the configuration file to prevent it from being used (deleting or editing the configuration file to remove the unwanted content are other options):

  sudo systemctl mask apt-news.service

  sudo systemctl mask esm-cache.service

  sudo mv /etc/apt/apt.conf.d/20apt-esm-hook.conf
/etc/apt/apt.conf.d/20apt-esm-hook.conf.disabled

• Alternatively, simply remove the ubuntu-advantage-tools package, which contains the /etc/apt/apt.conf.d/20apt-esm-hook.conf file.
• Another option is to remove the ubuntu-pro-client package.
• Lastly, there also is the possibility of enabling ESM, though that was not desirable for me.

In my case, it may have been the penultimate option on the list that I chose. In any case, I was rid of the unwanted message.

Fixing an Ansible warning about boolean type conversion

My primary use for Ansible is doing system updates using the inbuilt apt module. Recently, I updated my main system to Linux Mint 21 and a few things like Ansible stopped working. Removing instances that I had added with pip3 sorted the problem, but I then ran playbooks manually, only for various warning messages to appear that I had not noticed before. What follows below is one of these.

[WARNING]: The value True (type bool) in a string field was converted to u'True' (type string). If this does not look like what you expect, quote the entire value to ensure it does not change.

The message is not so clear in some ways, not least because it had me looking for a boolean value of True when it should have been yes. A search on the web revealed something about the apt module that surprised me.: the value of the upgrade parameter is a string, when others like it take boolean values of yes or no. Thus, I had passed a bareword of yes when it should have been declared in quotes as "yes". To my mind, this is an inconsistency, but I have changed things anyway to get rid of the message.

Ensuring that Flatpak remains up to date on Linux Mint 19.2

The Flatpak concept offers a useful way of getting the latest version of software like LibreOffice or GIMP on Linux machines because repositories are managed conservatively when it comes to the versions of included software. Ubuntu has Snaps, which are similar in concept. Both options bundle dependencies with the packaged software so that its operation can use later versions of system libraries than what may be available with a particular distribution.

However, even Flatpak depends on what is available through the repositories for a distribution, as I found when a software update needed a version of the tool. The solution was to add PPA using the following command and agreeing to the prompts that arise (answering Y, in other words):

sudo add-apt-repository ppa:alexlarsson/flatpak

With the new PPA instated, the usual apt commands were used to update the Flatpak package and continue with the required updates. Since then, all has gone smoothly as expected.

Upgrading avahi-dnsconfd on Ubuntu

This is how I got around a problem that occurred when I was updating a virtualised Ubuntu 16.04 instance that I have. My usual way to do this is using apt-get or apt from the command line and the process halted because a pre-removal script for the upgrade of avahi-dnsconf failed. The cause was its failure to disable the avahi daemon beforehand, so I needed to execute the following command before repeating the operation:

sudo systemctl disable avahi-daemon

Once the upgrade had completed, then it was time to re-enable the service using the following command:

sudo systemctl enable avahi-daemon

Ideally, this would be completed without such manual intervention. As it happens, there is a bug report for the unexpected behaviour. Hopefully, it will be sorted soon, but these steps will fix things for now.

Trying out a new way to upgrade Linux Mint in situ while going from 17.3 to 18.1

There was a time when the only recommended way to upgrade Linux Mint from one version to another was to do a fresh installation with back-ups of data and a list of the installed applications created from a special tool.

Even so, it never stopped me doing my own style of in situ upgrade, though some might see that as a risky option. More often than not, that actually worked without causing major problems in a time when Linux Mint releases were more tightly tied to Ubuntu's own six-monthly cycle.

Linux Mint releases now align with Ubuntu's Long Term Support (LTS) editions. This means major changes occur only every two years, with minor releases in between. These minor updates are delivered through Linux Mint's Update Manager, making the process simple. Upgrades are not forced, so you can decide when to upgrade, as all main and interim versions receive the same extended support. The recommendation is to avoid upgrading unless something is broken on your installation.

For a number of reasons, I stuck with that advice by sticking on my main machine with Linux Mint 17.3 instead of upgrading to Linux Mint 18. The fact that I broke things on another machine using an older method of upgrading provided even more encouragement.

However, I subsequently discovered another means of upgrading between major versions of Linux Mint that had some endorsement from the project. There still are warnings about testing a live DVD version of Linux Mint on your PC first and backing up your data beforehand. Another task is ensuring that you are upgraded from a fully up-to-date Linux Mint 17.3 installation.

When you are ready, you can install mintupgrade using the following command:

sudo apt-get install mintupgrade

When that is installed, there is a sequence of tasks that you need to do. The first of these is to simulate an upgrade to test for the appearance of untoward messages and resolve them. Repeating any checking, until all is well, gets a recommendation. The command is as follows:

mintupgrade check

Once you are happy that the system is ready, the next step is to download the updated packages so they are on your machine ahead of their installation. Only then should you begin the upgrade process. The two commands that you need to execute are below:

mintupgrade download
mintupgrade upgrade

After these complete, restart your system. In my case, the process worked well, with only my PHP installation requiring attention. I resolved a clash between different versions of the scripting interpreter by removing the older one, as PHP 7 is best kept for testing. Apart from reinstalling VMware Player and upgrading from version 18 to 18.1, I had almost nothing else to do and experienced minimal disruption. This is fortunate as I rely heavily on my main PC. The alternative of a full installation would have left me sorting things out for several days afterwards because I use a customised selection of software.

Reloading .bashrc within a BASH terminal session

BASH is a command-line interpreter that is commonly used by Linux and UNIX operating systems. Chances are that you will find yourself in a BASH session if you start up a terminal emulator in many of these, though there are others like KSH and SSH too.

BASH comes with its own configuration files and one of these is located in your own home directory, .bashrc. Among other things, it can become a place to store command shortcuts or aliases. Here is an example:

alias us='sudo apt-get update && sudo apt-get upgrade'

Such a definition needs there to be no spaces around the equals sign, and the actual command to be declared in single quotes. Doing anything other than this will not work, as I have found. Also, there are times when you want to update or add one of these and use it without shutting down a terminal emulator and restarting it.

To reload the .bashrc file to use the updates contained in there, one of the following commands can be issued:

source ~/.bashrc

. ~/.bashrc

Both will read the file and execute its contents so you get those updates made available so you can continue what you are doing. There appears to be a tendency for this kind of thing in the world of Linux and UNIX because it also applies to remounting drives after a change to /etc/fstab and restarting system services like Apache, MySQL or Nginx. The command for the former is below:

sudo mount -a

Often, the means for applying the sorts of in-situ changes that you make are simple ones too, and anything that avoids system reboots has to be good since you have less work interruptions.

ERROR: Can't find the archive-keyring

When I recently did my usual system update for the stable version Ubuntu GNOME, there were some updates pertaining to apt and the process failed when I executed the following command:

sudo apt-get upgrade

Usefully, some messages were issued and here's a flavour:

Setting up apt (0.9.9.1~ubuntu3.1) ...
ERROR: Can't find the archive-keyring
Is the ubuntu-keyring package installed?
dpkg: error processing apt (--configure):
subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
apt
E: Sub-process /usr/bin/dpkg returned an error code (1)

Web searches indicated the issue was missing files in /usr/share/keyring, which I didn't delete. Since apt was disabled due to the missing keyring files, installing software for fixes was impossible. My solution was to copy the /usr/share/keyring files from an Ubuntu GNOME 14.04 virtual machine to the same location on my Ubuntu GNOME 13.10 host. For others without this setup, I've included these files in a zip file below. While other solutions like Y PPA were mentioned, they required prior installation, making them useless when tools like Synaptic were unavailable. I'd appreciate information on other fixes that don't involve reinstalling the operating system, potential causes for the file loss, and how to prevent it.

Ubuntu Keyrings

How to compile and install Nightingale when PPA repositories fail on Ubuntu 13.10

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.

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 check out 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 subdirectory 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 the 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

The official line from Western Digital is this: 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 server's 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 in the Software Centre 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; this is found under Settings > Network on the web console. Next up is the actual file share name on the NAS; I have used a custom term 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; however, 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 afterwards, 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 be 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 similarly to mine.

Installing Citrix Receiver 13.0 in Ubuntu GNOME 13.10 64-bit

Installing the latest version of Citrix Receiver (13.0 at the time of writing) on 64-bit Ubuntu should be as simple as downloading the required DEB package and double-clicking on the file so that Ubuntu Software Centre can work its magic. Unfortunately, the 64-bit DEB file is faulty, so that means that the Ubuntu community how-to guide for Citrix still is needed. In fact, any user of Linux Mint or another distro that uses Ubuntu as its base would do well to have a look at that Ubuntu link.

For the sake of completeness, I still am going to let you in on the process that worked for me. Once the DEB file has been downloaded, the first task is to create a temporary folder where the DEB file's contents can be extracted:

mkdir ica_temp

With that in place, it then is time to do the extraction, and it needs two commands with the second of these need to extract the control file while the first extracts everything else.

sudo dpkg-deb -x icaclient- ica_temp
sudo dpkg-deb --control icaclient- ica_temp/DEBIAN

It is the control file that has been the cause of all the bother because it refers to unavailable dependencies that it really doesn't need anyway. To open the file for editing, issue the following command:

sudo gedit ica_temp/DEBIAN/control

Then change line 7 (it should begin with Depends:) to: Depends: libc6-i386 (>= 2.7-1), lib32z1, nspluginwrapper. While there are other software packages in there that Ubuntu no longer supports, they are not needed anyway. With the edit made, and the file saved, the next step is to build a new DEB package with the corrected control file:

dpkg -b ica_temp icaclient-modified.deb

Once you have the package, the next step is to install it using the following command:

sudo dpkg -i icaclient-modified.deb

If it fails, then you have missing dependencies and the following command should sort these before a re-run of the above command again:

sudo apt-get install libmotif4:i386 nspluginwrapper lib32z1 libc6-i386

With Citrix Receiver installed, there is one more thing that is needed before you can use it freely. This is to put Thawte security certificate files into /opt/Citrix/ICAClient/keystore/cacerts. What I had not realised until recently was that many of these already are in /usr/share/ca-certificates/mozilla and linking to them with the following command makes them available to Citrix Receiver:

sudo ln -s /usr/share/ca-certificates/mozilla/* /opt/Citrix/ICAClient/keystore/cacerts/

Another approach is to download the Thawte certificates and extract the archive to /tmp/. From there they can be copied to /opt/Citrix/ICAClient/keystore/cacerts and I copied the Thawte Personal Premium certificate as follows:

sudo cp /tmp/Thawte Root Certificates/Thawte Personal Premium CA/Thawte Personal Premium CA.cer /opt/Citrix/ICAClient/keystore/cacerts/

Until I found out about what was in the Mozilla folder, I simply picked out the certificate mentioned in the Citrix error message and copied it over like the above. Of course, all of this may seem like a lot of work to those who are non-tinkerers and I have added a repaired 64-bit DEB package that incorporates all of the above and should not need any further intervention aside from installing it using GDebi, Ubuntu's Software Centre, dpkg or anything else that does what's needed.