Andrew Hardiman's questions

In Skype notifications I have the following :

'A new update is available. Install the latest version via your package manager, then restart Skype'.

I have done the following:

sudo apt-get update
sudo apt-get install skypeforlinux

And the notification still persists.

I decided to completely remove Skype and install it again:

sudo apt-get autoremove --purge skypeforlinux

I reinstalled Skype like so:

sudo apt install ./skypeforlinux-64.deb

The notification still persists.

I removed Skype again and downloaded it via the Ubuntu Software Store GUI, I am still getting the notification.

I downloaded it directly from the Skype Web page, the 'Skype for Linux DEB' package, and I still get the same notification.

I deleted cache for good measure also.

My system states:

skypeforlinux is already the newest version (8.61.0.95)

0 to upgrade, 0 to newly install, 0 to remove and 16 not to upgrade.

However, I am still getting a notification within the application that an update is available. I have quit and restarted Skype numerous times. As well as carried out a system reboot several times.

Please could someone explain to me why this notification persists, and how I can get rid of it?

I want to ‘lockdown’ a particular key/value combination in dconf, so that only superusers will be able to modify that particular setting. In order to achieve this it is necessary to add a ‘lock’ to the system database, so that no equivalent key/value listed in a higher order database (in the dconf profile) can take precedence.

For a detailed explanation of the concept of a dconf profile and the related ‘key files’ please see the Gnome System Administrators Wiki.

From the System Admin Wiki:

Lockdown is supported by creating a 'locks' subdirectory in the key file directory (ie: /etc/dconf/db/local.d/locks). The files contained in this directory contain a list of keys to lock, one per line.

My keyfile directory shows as ‘ibus.d’, as opposed to ‘local.d’ given in the example:

:/etc/dconf/db/ibus.d$

By checking the dconf profile /etc/dconf/profile/ibus, this would appear correct:

Contents of 'ibus' file: user-db:user \ system-db:ibus

As per the Wiki:

1. Create an appropriate key file:

   ==> /etc/dconf/db/ibus.d/00-media-handling ==<

   [org/gnome/desktop/media-handling]

   automount=false

2. Create a ‘locks’ subdirectory and add an appropriate file:

   ==> /etc/dconf/db/ibus.d/locks/00_media-handling-lock ==<

   /org/gnome/desktop/media-handling/automount

In my case I have set, and locked, the automount key, for the org.gnome.desktop.media-handling schema, to 'false'.

Finally run sudo dconf update. For good measure I also reboot the machine.

The expected behaviour, upon attaching a USB drive, would be for the device not to automount. This, however, is not the case. If I attach a USB drive and run df:

/dev/sdb1 983344 192 983152 1% /media/user/xxxx-xxxx

Assuming I am at fault; I have started from ‘scratch’ numerous times, each time following the (identical) instructions from varied sources, including examples given on this site; example one and two. Each time to no avail. Please could you kindly enlighten as to where I could be going wrong? (Ubuntu 16.04)

I want to set the 'automount' key, for the ‘media-handling’ schema, to ‘false’, for all users on a single desktop machine.

I can do this individually, i.e. one user at a time, by using gsettings whilst logged-in as the specific user:

gsettings set org.gnome.desktop.media-handling automount false

To do this for each individual account, however, is somewhat arduous. I would like to set the same key to ‘false’ in a global fashion, so that the desired behaviour is observed globally, across all user accounts.

Using locate media-handling I have located the following ‘xml’ file:

/usr/share/glib-2.0/schemas/org.gnome.desktop.media-handling.gschema.xml

The file contains the following:

<schemalist gettext-domain="gsettings-desktop-schemas">
  <schema id="org.gnome.desktop.media-handling" path="/org/gnome/desktop/media-handling/">
    <key name="automount" type="b">
      <default>true</default>
      <summary>Whether to automatically mount media</summary>
      <description>If set to true, then Nautilus will automatically mount media such as user-visible hard disks and removable media on start-up and media insertion.</description>

I understood the files located here to be universal/global, and that any changes to these files, would affect all users globally. However, setting the value here to ‘false’ as no observable effect.

I have also found this answer and created the equivalent ‘override’ file:

/usr/share/glib-2.0/schemas$ ls | grep media-handling
org.gnome.desktop.media-handling.gschema.override.xml
org.gnome.desktop.media-handling.gschema.xml

..with the content:

[org.gnome.desktop.media-handling]
automount=”false”

I ran sudo glib-compile-schemas /usr/share/glib-2.0/schemas/ as instructed in the given answer, however there has been no observable effect. Why is this, assuming the given solution is correct?

How do I set the 'automount' key to ‘false’, in such a manner that it configures all user accounts? Once this is achieved, how do I prevent individual users from configuring their own account differently to the global rule?

Secondly, how does the system use the file /usr/share/glib-2.0/org.gnome.desktop.media-handling.gschema.xml, as my understanding would lead me to think it alters all user accounts, given its location in ….share/glib-2.0.. , however this is not the case?

(Ubuntu 16.04)

I want to configure Ubuntu (16.04) to prevent users from using removable media, specifically USB drives.

You can prevent automount as per.

gsettings set org.gnome.desktop.media-handling automount false

However, although this action disables auto-mounting of the device, it does not affect use of the device. I.E. as soon as you ‘open’ the USB icon on the desktop, the device mounts!

Running df upon opening the graphical USB desktop item:

/dev/sdb1 3780564 120 3780444 1% /media/user/xxxx-xxxx

I do not want the device to automount under any circumstances. You could argue that the device is still ‘automounting’ when you click on the desktop icon, as the user has not explicitly run a command to mount the device. For instance:

sudo mount /dev/sdb1 /media/user/xxxx-xxxx

Is there a schema/key combination in gsettings where I can set a value, in such a way, that only ‘root’ can use USB devices? In other words, I do not want USB devices to be accessible unless explicitly mounted by root.

I have also found these two answers; one and two.

However, as a relatively inexperienced user, I'm hesitant to implement the instructions as given, as the answer mentions to "blacklist the kernel driver".. whilst I do not doubt the validity of the information given, this gives me the impression that it is really for advanced users only. Likewise, the 'man' page for modprobe refers to "adding/removing modules to the Linux Kernel".

Is this the only way to go about blocking USB access, or is there a Schema/Key combination in gsettings where I can simply set the value of a key as appropriate?

To clarify, I am explicitly referring to USB storage/drives, as I have a keyboard and pointer connected via USB.

For example, if I run the following command dpkg -l ‘*compiz*’ the output is as follows:

Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version      Architecture Description
+++-==============-============-============-=================================
pi  compiz         1:0.9.12.2+1 all          OpenGL window and compositing man
ii  compiz-core    1:0.9.12.2+1 amd64        OpenGL window and compositing man
un  compiz-core-ab <none>       <none>       (no description available)
[more output deleted]

The output is a little cryptic. There are several detailed explanations on askubuntu, of which, example, is one. Likewise, man dpkg and man dpkg-query give similar explanations.

The first character in the first field, ‘p’, in our example output above, indicates the desired status of the package. Which is the status that the packaging system thinks the package should be in.

What is the underlying meaning of the desired status? I.e. Why does the packaging managing system have an idea of what status a package should be in? I could see that an intelligent system would recommend (or desire) a package to be purged if it was only ever used as a dependency to an already removed parent package. However, this is not the case in our example.

In our example, the package ‘compiz’ is installed, however dpkg believes it should be purged, or at least that it is desirable that the package is purged, why is this? Moreover, how does this particular field work in general? I.e. how does the system decide on a ‘desired status’ for a package and what are the underlying reasons for this functionality?

I can copy a directory like so:

~$ cp -r ./Desktop/ /tmp/

Similarly, if I just wanted to copy the files from within a directory, I could do so:

~$ cp -r ./Desktop/. /tmp/

Things become a little more tricky if I want to copy the source directory into a target directory, that is a sub-directory of the source. i.e. copy a directory into itself. For example:

~$ cp -r ./Desktop/ ./Desktop/sub/

Would throw the following error: cp: cannot copy a directory, './Desktop/', into itself, './Desktop/sub/'

This can be circumnavigated, somewhat, using extglob, like so:

~$ cp -r ./Desktop/!(sub) ./Desktop/sub/

However, this last command is dependent on the directory sub already existing.

How can you copy a directory into itself, in such a fashion that the command to do so creates the sub directory at the same time?

I have decided to join the Linux community and have chosen Ubuntu for my initial foray into this new and exciting world.

I am teaching myself the basics using a well recommended text book. I am currently working through the chapter on using the Compiz Window Manager.

On Ubuntu systems, Compiz can be configured using the gconftool-2 command-line utility.

In the text, the following command examines the settings for the Compiz Wobbly Windows plug-in:

gconftool-2 -R /apps/compiz/plugins/wobbly

However, when I enter this command, nothing happens, at all, and the command line simply returns to the next line, awaiting the next command.

My thoughts:

The text I am using is dated and written for Ubuntu 10.04 LTS. I am using Ubuntu 16.04.2. There will, therefore, clearly be differences. I've done the following:

• I've checked and gconftool-2 is still a legitimate command.
• I've checked and Compiz is actively running.
• I’ve searched for the Compiz plugin wobbly, which is also installed.
• I can see that Compiz is not located in the directory given in the text, i.e. it does not appear under in the following directory ‘/apps/compiz/plugins/wobbly’.

Therefore, I concluded the gconftool-2 command is not working as intended because the directory given ‘/apps/compiz/plugins/wobbly’ is no longer valid in the current version of Ubuntu. Therefore, to resolve the issue, I would simply need to locate the relevant file(s). However, when I run ‘locate compiz’ in the terminal, the list of files returned has to be in excess of a hundred. I ran ‘locate wobbly’ which returned only three files, however running the following command does not work either:

gconftool-2 -R /usr/share/compiz/wobbly

How do you examine and set specific repository keys and new values for the Compiz Window Manager, and its associated plugins, using the command-line in Ubuntu 16.04? How has this changed since 10.04 and how does one know which files to examine, there are simply too many Compiz files to know where to start?