How to display the times in various time zones from the LXDE Panel

I normally check the time in the time zone of family, friends and colleagues who live in various places around the World before I call or message them. In KDE Plasma on my laptop it is possible to configure the digital clock widget to display the times in a list of time zones of my choice when I hover the mouse pointer over the widget. However, my family’s PC has Lubuntu 18.04 installed, which uses LXDE, and the digital clock on the LXDE Panel does not have that ability. Therefore I installed the GUI utility gworldclock in Lubuntu 18.04:

$ sudo apt-get install gworldclock

I added it to the ‘Application Launch and Task Bar’ plugin on the LXDE Panel, and a clock icon is now displayed on the Panel.

gworldclock icon on Application Launch and Task Bar on LXDE Panel

gworldclock icon on Application Launch and Task Bar on LXDE Panel

When I click the clock icon, a window opens on the Desktop and displays the date and time at each of the World locations I configured in gworldclock (‘Options’ > ‘Add Timezone’). Excellent, and almost as convenient as the World time feature in the Digital Clock widget in KDE Plasma 5.

gworldclock window default size

gworldclock window default size

I have configured gworldclock to display a list of ten additional time zones when I click on the clock icon on the Application Launch and Task Bar on the Panel. However, the size of the pop-up gworldclock window was relatively small; only six of the eleven time zones were visible, so I had to use the window’s scroll bar in order to view some of the configured time zone entries. I therefore made some changes in LXDE in order to display a larger gworldclock window showing all eleven time zones. This is how I did it.

1. I installed wmctrl:

$ sudo apt-get install wmctrl

2. I created a hidden Bash script ~/ containing the following:

gworldclock &
sleep 0.5s
wmctrl -F gworldclock -r gworldclock -e 0,500,300,300,340

and made it executable:

$ chmod +x ~/

See man wmctrl for the meaning of the options in the above-mentioned Bash script.

3. I created the Desktop Configuration File ~/.local/share/applications/gworldclockfitzcarraldo.desktop containing the following:

[Desktop Entry]
Comment=See the time in other timezones
GenericName=World Clock
Comment[fr]=Voir l'heure dans d'autres fuseaux horaires

4. I edited the file ~/.config/lxpanel/Lubuntu/panels/panel and added an entry for the new Desktop Configuration File to the end of list for the Application Launch and Task Bar, as shown in the following excerpt from the file:

Plugin {
  Config {
    Button {
    Button {
    Button {
    Button {
    Button {
    Button {
    Button {

Then I logged out and back in again. Now, when I click on the clock icon on the Panel, the gworldclock window opens at the location and size specified by the wmctrl command in the Bash script I created.

gworldclock window resized by the Bash script

gworldclock window resized by the Bash script


Configure a keyboard shortcut in Lubuntu 18.04 to take a screenshot of a screen region

As installed, Lubuntu 18.04 is configured so that the user can capture a screenshot of the whole screen by pressing the PrtScrn key, and a screenshot of the active window by pressing Alt+PrtScrn. However, no keyboard shortcut is configured to enable the user to capture a user-specified region of the screen.

Now, as it happens, the ‘-s‘ option of the scrot command allows a region of the screen to be captured and saved. The man page for scrot tells us:

-s, --select
Interactively select a window or rectangle with the mouse.

So here is how to configure a keyboard shortcut to do that in Lubuntu 18.04.

Open the file ~/.config/openbox/lubuntu-rc.xml in a text editor (either nano from the command line or LXTerminal from the GUI) and look for the following lines:

    <keybind key="Print">
      <action name="Execute">
        <command>lxsession-default screenshot</command>
    <keybind key="A-Print">
      <action name="Execute">
        <command>lxsession-default screenshot window</command>

Append the following lines to that group of lines:

    <keybind key="C-A-Print">
      <action name="Execute">
        <command>scrot -s</command>

The new group of lines should then look like this:

    <keybind key="Print">
      <action name="Execute">
        <command>lxsession-default screenshot</command>
    <keybind key="A-Print">
      <action name="Execute">
        <command>lxsession-default screenshot window</command>
    <keybind key="C-A-Print">
      <action name="Execute">
        <command>scrot -s</command>

Now logout and login again.

If you now press Ctrl+Alt+PrtScrn and use your mouse to select a rectangular region of the screen, a screenshot of that region will be saved automatically to your home directory. Simple.

You just have to remember:

PrtScrn — Captures the entire screen.
Alt+PrtScrn — Captures the active window.
Ctrl+Alt+PrtScrn — Captures the area of the screen you select with the mouse.

Installing Dropbox in Gentoo Linux following the recent restrictions introduced for Dropbox for Linux

In a 2013 post I explained how I installed Dropbox in Gentoo Linux running KDE 4. The Dropbox company has recently imposed some restrictions in the Linux client, so this is to explain what I did to get Dropbox working again in my two Gentoo Linux installations, both using the ext4 filesystem (unencrypted) and, these days, KDE Plasma 5.

Both my laptops running Gentoo Linux had a version of Dropbox installed via the Portage package manager: dropbox-45.3.88 in the case of the laptop running Gentoo amd64, and dropbox-48.3.56 in the case of the laptop running Gentoo ~amd64. Recently a Dropbox window popped up, warning me to upgrade Dropbox to the latest version within seven days otherwise the client would no longer be able to sync with the remote Dropbox server. I also received an e-mail from the Dropbox company titled ‘[Action required] We’re updating Linux system requirements‘ informing me that the only supported Linux distributions from now on would be Ubuntu 14.04 or higher and Fedora 21 or higher, and furthermore that the client will only work on an unencrypted ext4 filesystem. As both my Gentoo installations use unencrypted ext4, I was OK on that score, but I still had the problem that an up-to-date Dropbox ebuild is not available for Gentoo and the old Dropbox versions I was using no longer sync. However, I managed to install the latest version of Dropbox (currently 55.4.171) in Gentoo, and it works fine. The Dropbox client’s icon is on the KDE Plasma 5 Panel, and the local Dropbox directory is being sync’ed correctly. Below I explain what I did.

1. I selected ‘Quit Dropbox’ from the old Dropbox client’s menu, and the Dropbox icon disappeared from the Panel.

2. I removed the Dropbox daemon from the list of script files to be started at login (‘System Settings’ > ‘Startup and Shutdown’ > ‘Autostart’).

3. I unmerged (uninstalled) the dropbox package:

clevow230ss /home/fitzcarraldo # emerge --ask --depclean dropbox

4. I deleted the directories ~/.dropbox and ~/.dropbox-dist but kept the directory ~/Dropbox and its contents.

fitzcarraldo@clevow230ss ~ $ rm -rf ~/.dropbox ~/.dropbox-dist

5. I followed the instructions under ‘Dropbox Headless install via command line‘ on the Dropbox Website to re-install the latest version of the daemon and client:

fitzcarraldo@clevow230ss ~ $ cd ~ && wget -O - "" | tar xzf -

6. I configured KDE Plasma 5 to start ~/.dropbox-dist/dropboxd at login (‘System Settings’ > ‘Startup and Shutdown’ > ‘Autostart’ > ‘Add Script…’).

7. I launched ~/.dropbox-dist/dropboxd manually from a Konsole window. The Dropbox client icon appeared on the Panel and I was prompted to login to my Dropbox account via a Web browser, as per the instructions on the Dropbox Website (see link in in Step 5):

If you’re running Dropbox on your server for the first time, you’ll be asked to copy and paste a link in a working browser to create a new account or add your server to an existing account. Once you do, your Dropbox folder will be created in your home directory.

8. I logged in to my Dropbox account via the Firefox browser. As soon as I had logged in via the browser, a message appeared in the browser window informing me that “Your computer was successfully linked to your account”, and the Dropbox client icon appeared on the Panel and showed that the contents of ~/Dropbox were being synchronised.

Everything seems to be working as before. The Dropbox icon on the Panel has the same menu items it had previously. ‘Preferences…’ shows the Dropbox version as v55.4.171. I have not ticked ‘Start Dropbox on system startup’ under Dropbox Preferences because I configured automatic startup using KDE Plasma 5 ‘System Settings’ as described in Step 6 above, and the Dropbox daemon is indeed started automatically when I login.

The Dropbox Website’s instructions (see link in Step 5) also include the following:

Download this Python script to control Dropbox from the command line. For easy access, put a symlink to the script anywhere in your PATH.

I did download that Python script and made it executable:

fitzcarraldo@clevow230ss ~/Dropbox $ chmod +x

However the Python 3.6 interpreter in my Gentoo Linux installations report a syntax error in the script when I run it, I assume because it was written for a different version of Python:

fitzcarraldo@clevow230ss ~/Dropbox $ ./ 
  File "./", line 233
    except OSError, e:
SyntaxError: invalid syntax

Anyway, as the Dropbox client icon is on the KDE Plasma 5 Panel and I can control Dropbox from there, I see no need for the Python script.

9. My Gentoo installations have a Bash script ~/ that I had created to be launched by a Desktop Configuration file ~/Desktop/Dropbox.desktop with a nice icon which I double-click on if I want to relaunch the Dropbox daemon (if I previously quit Dropbox from the client’s menu, for example). I had to modify ~/ by replacing the command ‘dbus-launch dropbox start > /dev/null‘ with the command ‘/home/fitzcarraldo/.dropbox-dist/dropboxd‘ as shown below.

notify-send 'Launching Dropbox' 'Daemon will be (re)started in 20 seconds' --icon=dialog-information
sleep 20s
ps auxww | awk '$0~/dropbox/&&$0!~/awk/{print $2}' | xargs kill


[Desktop Entry]
Comment[en_GB]=(re)launch Dropbox daemon
Comment=(re)launch Dropbox daemon

10. At the moment Dropbox is working fine again in my Gentoo installations. However, I noticed that Gentoo Linux user zsitvaij posted the following comment in a Gentoo Forums thread:

On every dropbox update, I have to remove ~/.dropbox-dist/dropbox-lnx./ to avoid having it crash on launch, works fine after until they update again.

I do not know if that will be necessary in my case, as I have not yet had to upgrade Dropbox from the Version 55.4.171 that I recently installed. When a new version of Dropbox becomes available I will update this post to confirm whether or not I had to do anything to keep Dropbox working.

Addendum (1 October 2018): With reference to my addendum of 2 September 2018, if you are using OpenRC it is possible to automate the deletion of the file ~/.dropbox-dist/dropbox-lnx.x86_64-/ by creating a Bash script /etc/local.d/40dropbox.start containing the following:

if [ -e /home/fitzcarraldo/.dropbox-dist/dropbox-lnx.x86_64-*/ ]
    rm /home/fitzcarraldo/.dropbox-dist/dropbox-lnx.x86_64-*/

Replace my username with your username, obviously. Of course the conditional test could be dispensed with and the script could just contain the shebang line and the rm line, which would still work even if the file does not exist, but it feels a bit tidier to only attempt to delete the file if it actually exists.

Addendum (2 September 2018):I have just installed Dropbox Version 56.4.94 in my Gentoo ~amd64 installation and I had to use the command shown below once in order to stop the daemon segfaulting when I entered the command ~/.dropbox-dist/dropboxd in a Konsole window:

fitzcarraldo@clevow230ss ~/Dropbox $ rm ~/.dropbox-dist/dropbox-lnx.x86_64-56.4.94/

Addendum (31 August 2018): The Python script that can be downloaded from the Dropbox Web site (see Step 8 above) is old, as can be seen in the comments in the header of the script:

# Dropbox frontend script
# This file is part of nautilus-dropbox 2015.10.28.

It is written in Python 2. Although I do not need to use it, I managed to get it to run in my Gentoo installations by replacing the shebang line ‘#!/usr/bin/python‘ with ‘#!/usr/bin/env python2‘. This works in my Gentoo installations because they have both Python 2.7 and Python 3.6 installed. When I now run I see the following:

fitzcarraldo@clevow230ss ~/Dropbox $ ./ 
Dropbox command-line interface


Note: use dropbox help  to view usage for a specific command.

 status       get current status of the dropboxd
 throttle     set bandwidth limits for Dropbox
 help         provide help
 stop         stop dropboxd
 running      return whether dropbox is running
 start        start dropboxd
 filestatus   get current sync status of one or more files
 ls           list directory contents with current sync status
 autostart    automatically start dropbox at login
 exclude      ignores/excludes a directory from syncing
 lansync      enables or disables LAN sync
 sharelink    get a shared link for a file in your dropbox
 proxy        set proxy settings for Dropbox

fitzcarraldo@clevow230ss ~/Dropbox $ ./ status
Up to date
fitzcarraldo@clevow230ss ~/Dropbox $ ./ running
fitzcarraldo@clevow230ss ~/Dropbox $ ./ filestatus ~/Dropbox/Getting\ Started.pdf 
/home/fitzcarraldo/Dropbox/Getting Started.pdf: up to date
fitzcarraldo@clevow230ss ~/Dropbox $

Notice that the command ./ running does not return anything even though the daemon is definitely running, so I do not trust the script anyway.

How to move a mouse pointer automatically in Linux to simulate user activity

My various Linux installations all have Suspend to RAM enabled with a specified timeout. Sometimes I want to override the timeout; for example if I have left something running in a terminal window or I have left the package manager in a virtual machine upgrading the guest installation. I could of course launch the system’s power manager GUI and temporarily disable Suspend to RAM or increase the timeout, but I prefer to use a shell script, launched by double-clicking on a Desktop icon, to move the mouse pointer automatically to fool the OS into believing someone is using the machine. There are various ways of doing this, but the method I prefer is given below.

1. Create a Bash script ‘/home/fitzcarraldo/‘ containing the following:

# Script to keep mouse pointer moving so that, for example, Suspend to RAM timeout does not occur.
# The mouse pointer will move around its current position on the screen, i.e. around any position
# on the screen where you place the pointer. However, if you prefer it to move around the centre
# of the screen then change mousemove_relative to mousemove in the xdotool command below.
# Set LENGTH to 0 if you do not want the mouse pointer to actually move.
# Set LENGTH to 1 if you want the mouse pointer to move just a tiny fraction.
# Set LENGTH to e.g. 100 if you want to see more easily the mouse pointer move.
# Set DELAY to the desired number of seconds between each move of the mouse pointer.
while true
    for ANGLE in 0 90 180 270
	xdotool mousemove_relative --polar $ANGLE $LENGTH
        sleep $DELAY

Do not forget to make the script executable.

As you can see in the above script, it is possible to control how much, if at all, the mouse pointer actually moves on the screen. While the script is running you are not precluded from moving the mouse manually as well.

2. Create a Desktop Configuration File ‘/home/fitzcarraldo/Desktop/keep_mouse_moving.desktop‘ containing the following:

[Desktop Entry]
Comment[en_GB]=Keep mouse moving automatically
Comment=Keep mouse moving automatically
Exec=xterm -iconic -e "bash -c /home/fitzcarraldo/"
GenericName[en_GB]=Keep mouse moving automatically
GenericName=Keep mouse moving automatically

(In installations that use KDE or GNOME I replace the ‘LXDE‘ above with ‘KDE‘ or ‘GNOME‘, as appropriate.)

3. Use the distribution’s package manager to install xterm and xdotool if they are not already installed.

4. Whenever I want to fool the OS into thinking a user is moving the mouse, I double-click on the mouse icon on the Desktop and the Bash script is launched in a minimised xterm window, which I can see on the Panel. I can then leave the installation knowing that it will not suspend to RAM and that the screensaver will not kick in. When I want to stop the mouse pointer moving automatically, I simply click on the xterm bar on the Panel to open the xterm window, and click on Close (×) on the window’s title bar to terminate xterm and the shell script.

Note that the X Windows Toolkit option -iconic may not work in some Desktop Environments (GNOME, for example), in which case you can minimise the xterm window manually if you want, or use another terminal emulator.

By the way, if you use GNOME and it is currently configured not to display icons on the Desktop, you can change this by using the following command:

user $ gsettings set org.gnome.desktop.background show-desktop-icons true

Of course you are not obliged to have the .desktop file on the Desktop; it could be in any directory.

Getting the lock screen to work reliably when resuming from suspension in a single-seat, multi-user Lubuntu 18.04 installation

In an earlier post I described my attempt at getting the lock screen to work reliably in the single-seat, multi-user Lubuntu 17.10 installation on my family’s desktop PC. Although the modifications described in that post seemed to improve matters somewhat, users were still not always able to login from the LightDM greeter screen after resuming from Suspend to RAM in the following situation:

  1. User_A logs in to User_A’s account but does not log out after using the account.
  2. User_B clicks on ‘Logout’ > ‘Switch User’ to log in to User_B’s account but does not log out.
  3. User_A clicks on ‘Logout’ > ‘Switch User’ to get back to User_A’s account.
  4. User_A allows his/her session to timeout and suspend to RAM.
  5. User_B presses a key on the keyboard to resume from suspension, and the LightDM lock screen is displayed.
  6. User_B enters his/her password and then clicks on ‘Unlock’, but the LightDM lock screen remains on display and nobody can log in any more, although the keys on the lock screen are still clickable.

When this occurs, the only way users can access their Desktop is to click on the Power icon in the top right corner of the lock screen and select ‘Restart…’.

The Software Updater in Lubuntu 17.10 recently offered me the choice of upgrading to Lubuntu 18.04, which I accepted. The upgrade was performed and the only hitch that resulted was an incorrect initramfs, which was simple enough to fix (see my post Lubuntu 18.04 ‘Gave up waiting for suspend/resume device’). However, the above-mentioned problem of unlocking after resuming from suspension still occurred in Lubuntu 18.04. Below are the changes I made since the modifications described in my post Getting the lock screen to work properly when resuming from Suspend-to-RAM with multiple sessions in Lubuntu 17.10 (the other changes in that post remain), which seem to have cured the problem.

Change to Item 2 in my earlier post

I reverted the Exec line in /etc/xdg/autostart/light-locker.desktop back to how it was originally following installation of Lubuntu:

user $ grep Exec /etc/xdg/autostart/light-locker.desktop

Change to Item 3 in my earlier post

I deleted the file /lib/systemd/system-sleep/hang-fix that I had previously created:

user $ sudo rm /lib/systemd/system-sleep/hang-fix

Change to Item 7 in my earlier post

The Xfce Power Manager ‘Security’ tab for each user now has ‘Lock screen when system is going for sleep’ ticked:

Light Locker

  • Automatically lock the session: Never
  • Delay locking after screensaver for: ‘1 Seconds’ is greyed out
  • ‘Lock screen when system is going for sleep’ is ticked

The full Xfce Power Manager settings for each user (see the file ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-power-manager.xml in each user’s home directory) are now configured as follows:

<?xml version="1.0" encoding="UTF-8"?>

<channel name="xfce4-power-manager" version="1.0">
  <property name="xfce4-power-manager" type="empty">
    <property name="power-button-action" type="empty"/>
    <property name="show-tray-icon" type="empty"/>
    <property name="brightness-switch-restore-on-exit" type="int" value="1"/>
    <property name="brightness-switch" type="int" value="0"/>
    <property name="presentation-mode" type="bool" value="false"/>
    <property name="inactivity-on-ac" type="uint" value="30"/>
    <property name="blank-on-ac" type="int" value="10"/>
    <property name="dpms-on-ac-sleep" type="uint" value="0"/>
    <property name="dpms-on-ac-off" type="uint" value="0"/>
    <property name="brightness-on-ac" type="uint" value="9"/>
    <property name="lock-screen-suspend-hibernate" type="bool" value="true"/>
    <property name="logind-handle-lid-switch" type="bool" value="false"/>
    <property name="dpms-enabled" type="bool" value="false"/>
    <property name="general-notification" type="bool" value="true"/>

Additional modifications

In another of my posts (Prevent Lubuntu 17.10 from leaving an external HDD mounted incorrectly for other users) I explained the modifications I made in Lubuntu 17.10 for a single-seat, multi-user installation to work properly with a permanently connected external USB HDD. However, I recently noticed the following problems resulting from those modifications:

A. The following error message in the LightDM log file /var/log/lightdm/lightdm.log:

[SeatDefaults] is now called [Seat:*], please update this configuration

So I changed the contents of the file /etc/lightdm/lightdm.conf.d/10_lubuntu.conf from:




B. The following error message in the LightDM log file/var/log/lightdm/lightdm.log when the USB external HDD happened to not be mounted at the time:

DEBUG: Launching process 8569: /etc/lightdm/lightdm.conf.d/
DEBUG: Process 8569 terminated with signal 11

So I changed the contents of my Bash script /etc/lightdm/lightdm.conf.d/ from:

udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015


STATUS=`mount | grep $(readlink -f /dev/disk/by-uuid/C6576A087368B015 )`
if [[ ! -z $STATUS ]]; then
    udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015
exit 0


It is early days, but so far the login problem for other users after resuming from suspension has not reoccurred since I made the latest changes. I am not sure if the modifications described in my post ‘Prevent Lubuntu 17.10 from leaving an external HDD mounted incorrectly for other users‘ contributed to (or caused) the login problem, or whether one or more of systemd-logind, LightDM, LightDM GTK+ Greeter, Light Locker and Xfce Power Manager are to blame (since they have to work holistically to provide the required functionality). It is frustrating not knowing the root cause of the problem, but at least my family no longer has to worry about being able to log in if a family member has not logged out and left the PC to suspend.

Installing the Onboard on-screen keyboard in Gentoo Linux

Onboard on-screen keyboard with the Compact British English layout, Droid theme and international character selection enabled for the long-press action

Onboard on-screen keyboard configured with the British English layout, Droid theme and international character selection enabled for the long-press action

The most sophisticated and polished virtual keyboard I have seen so far in Linux is Onboard, the on-screen keyboard previously provided in Ubuntu prior to the switch to GNOME 3. The current version of Onboard is 1.4.1 and it can be installed and used in other Linux distributions and desktop environments. Thanks to Gentoo Linux user wjn an ebuild is available in the wjn-overlay overlay and can be installed from there via Portage. However, I prefer to use a local overlay so I copied the ebuild to my local overlay and installed it from there instead. Here is what I did to install app-accessibility/onboard in the Gentoo Stable installation running KDE Plasma 5 on my Clevo W230SS laptop:

1. I first made sure the preferred Python interpreter was selected (I should have done that when the Gentoo Linux developers recently replaced Python 3.5 with Python 3.6 in the default Python targets for Gentoo installations):

root # grep PYTHON /etc/portage/make.conf
PYTHON_TARGETS="python2_7 python3_6"
root # eselect python list
Available Python interpreters, in order of preference:
  [1]   python2.7
  [2]   python3.5 (uninstalled)
  [3]   python3.4
  [4]   python3.6 (fallback)
root # eselect python set 4
root # eselect python list 
Available Python interpreters, in order of preference:
  [1]   python3.6
  [2]   python2.7
  [3]   python3.5 (uninstalled)
  [4]   python3.4

2. Then I copied the ebuild to my local overlay:

root # mkdir -p /usr/local/portage/app-accessibility/onboard/files
root # cd /usr/local/portage/app-accessibility/onboard/files/
root # wget onboard-1.4.1-remove-duplicated-docs.patch
root # cd ..
root # wget wget
root # ebuild onboard-1.4.1.ebuild manifest

3. As I am using using Gentoo Stable I unmasked the ebuild by keyword:

root # nano /etc/portage/package.accept_keywords/onboard
root # cat /etc/portage/package.accept_keywords/onboard
=app-accessibility/onboard-1.4.1 **

4. Then I installed the package:

root # emerge onboard
root # eix onboard
[I] app-accessibility/onboard [1]
     Available versions:  (~)1.4.1^m {PYTHON_TARGETS="python3_5 python3_6"}
     Installed versions:  1.4.1^m(15:28:57 25/06/18)(PYTHON_TARGETS="python3_6 -python3_4 -python3_5")
     Description:         Onscreen keyboard for everybody who can't use a hardware keyboard

[1] "local_overlay" /usr/local/portage

Icons for Onboard and Onboard Settings were added to the KDE Application Launcher’s menu (Applications > Utilities) and they can be launched from there or by entering the command ‘onboard‘ in a Konsole window under the user’s account.

5. The only thing that did not work ‘out of the box’ in KDE Plasma 5.12.5 in Gentoo was selecting ‘Help’ from the pop-up menu displayed by clicking on the Onboard icon on the Plasma 5 Panel:

FileNotFoundError: [Errno 2] No such file or directory: ‘/usr/bin/yelp’: ‘/usr/bin/yelp’

This was simply because the package gnome-extra/yelp had not been installed in my KDE installation. Now, I could have just installed it separately:

root # emerge yelp

but I chose intead to edit the onboard ebuild to add yelp to the list of runtime dependencies:


and I then re-installed the package, which then automatically installed yelp and its dependencies:

root # ebuild onboard-1.4.1.ebuild manifest
root # emerge onboard

Onboard is a nice utility, and I hope its developers continue to maintain and develop it even though Ubuntu now uses the GNOME 3 on-screen keyboard instead, as it can be used in other desktop environments and in other Linux distributions.

Getting the lock screen to work properly when resuming from Suspend-to-RAM with multiple sessions in Lubuntu 17.10


What is it with Linux and lock screens?! There are umpteen posts on the Web by Linux users having trouble with lock screens, particularly the LightDM session locker Light Locker. Well, here is my contribution.

Lubuntu 17.10 is installed on my family’s desktop PC (single seat, multiple users). Lubuntu 17.10 uses systemd-logind, LightDM, Light Locker and Xfce Power Manager, and they do not work properly holistically in my experience. To confuse matters further, Lubuntu 17.10 also has XScreenSaver installed, which also has lock-screen capabilities.

In Lubuntu 17.10 on my family’s desktop PC, Light Locker displays the LightDM GTK+ Greeter screen when anyone wakes/resumes the PC from suspension by pressing a key on the USB keyboard, and users should then be able to log in by selecting their username from the pull-down list on the LightDM GTK+ Greeter screen and entering their password. However, if only a single user session existed when the PC suspended automatically (i.e. by timeout), upon resuming from suspension a black screen with a white padlock icon and the following message in white/grey text from light-locker would appear:

This session is locked
You’ll be redirected to the unlock
dialog automatically in a few seconds

But then nothing else happened; the above-mentioned message remained on display. I could press Ctrl+Alt+F1, login on TTY1 and enter the command ‘loginctl unlock-sessions‘ to get back to the Desktop, but that is not something the rest of my family would know how to do or be comfortable doing. In any case, I have only given sudo rights to one other member of the family.

Another problem would occur if the PC was left to suspend automatically with more than one user still logged in (i.e. more than one session). Although Light Locker would display the LightDM GTK+ Greeter screen upon resuming from suspension, and users could select their username from the pull-down list and enter their password, the LightDM GTK+ Greeter screen would remain on display and it would no longer be possible to re-enter a password (although it was still possible to select users from the pull-down list of users, and to select ‘Suspend’, ‘Restart…’ and ‘Shutdown…’ from the pull-down power menu). However, if users suspended the PC manually by selecting ‘Logout’ > ‘Lock Screen’ from the Lubuntu Menu, upon waking/resuming it was possible to enter their password on the LightDM GTK+ Greeter screen to return to their Desktop.

In this article I explain what I did to try and rectify these problems.

By the way, note that hibernation is disabled by default in Lubuntu 17.10 and you may need to make further changes if you want to enable hibernation as well. For example, does the PC have a swap partition, and is it large enough to enable hibernation? Also see the article: How to Enable Hibernate in Ubuntu 17.10 for possible help.


The package light-locker-settings was not installed in Lubuntu 17.10. Do not install it. If it happens to be installed do not use ‘Preferences’ > ‘Light Locker Settings’, as it makes the Exec entry in the user’s light-locker.desktop file just ‘Exec=‘ or ‘Exec=light-locker‘. In fact, having installed light-locker-settings manually to check what could be configured via its GUI, I uninstalled it in order to stop anyone using it. (Under ‘Screensaver’, the Light Locker Settings GUI displays the following message: ‘Your screensaver settings are managed by Xfce Power Manager.’ and there is a button ‘Open’ to click on to launch the Xfce Power Manager settings GUI.) Presumably this was why it was not included when Lubuntu 17.10 was first installed to the HDD.

1.  I removed any light-locker.desktop files of individual users, leaving only the system-wide file:

$ sudo rm /home/*/.config/autostart/light-locker.desktop
$ sudo updatedb
$ locate light-locker.desktop

2.  I edited the system-wide light-locker.desktop file to contain the following command to execute Light Locker:

$ grep Exec /etc/xdg/autostart/light-locker.desktop
Exec=light-locker --lock-after-screensaver=0 --no-lock-on-suspend --no-lock-on-lid --no-idle-hint

3.  I created the Bash script file /lib/systemd/system-sleep/hang-fix for systemd to run when suspending and resuming from suspension, with the permissions shown:

case "$1" in
        date | tr -d '\n' >> /home/fitzcarraldo/sleep.log
        echo " going to sleep." >> /home/fitzcarraldo/sleep.log
        chvt 1
        loginctl unlock-sessions
        date | tr -d '\n' >> /home/fitzcarraldo/sleep.log
        echo " waking from sleep." >> /home/fitzcarraldo/sleep.log
        loginctl lock-sessions
        chvt 7
        exit $NA
exit 0

$ sudo chmod 755 /lib/systemd/system-sleep/hang-fix
$ ls -la /lib/systemd/system-sleep/hang-fix
-rwxr-xr-x 1 root root 581 Apr 14 08:09 /lib/systemd/system-sleep/hang-fix

The above script is a hack to get around the problem of Light Locker resuming and apparently not knowing which session to unlock. I used the loginctl commands in this script rather than the Xfce Power Manager suspend options and Light Locker options such as ‘--late-locking‘ and ‘--lock-on-suspend‘ because I found that the Light Locker options and the Xfce Power Manager options did not fix the problem.

4.  I created two files for Polkit (to cover all Polkit versions to date) with the permissions as shown below.

4.1  The file /etc/polkit-1/rules.d/85-suspend.rules with the following contents:

polkit.addRule(function(action, subject) {
    if ( == "org.freedesktop.login1.suspend" || == "org.freedesktop.login1.suspend-multiple-sessions" || == "org.freedesktop.login1.hibernate" || == "org.freedesktop.login1.hibernate-multiple-sessions")
        return polkit.Result.YES;

If you do not have a swap partition large enough to enable hibernation, or you do not want to allow the PC to hibernate, use the following instead of the above:

polkit.addRule(function(action, subject) {
    if ( == "org.freedesktop.login1.suspend" || == "org.freedesktop.login1.suspend-multiple-sessions")
        return polkit.Result.YES;

$ sudo chmod 755 /etc/polkit-1/rules.d
$ sudo chmod 644 /etc/polkit-1/rules.d/85-suspend.rules
$ ls -la /etc/polkit-1/rules.d/85-suspend.rules
-rw-r--r-- 1 root root 359 Apr 19 22:14 /etc/polkit-1/rules.d/85-suspend.rules

4.2  The file /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla with the following contents:

[Allow suspending with lock screen]

If you do not have a swap partition large enough to enable hibernation, or you do not want to allow the PC to hibernate, use the following instead of the above:

[Allow suspending with lock screen]

$ sudo chmod 644 /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla
$ sudo ls -la /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla
-rw-r--r-- 1 root root 191 Apr 20 10:01 /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla

The above files are intended to get rid of the following error messages in a pop-up window and pop-up notification ballon, respectively, that prevent the OS from suspending automatically:

Authentication is required for suspending
the system while other users are logged in.

Power Manager
Method call timed out

By the way, the version of Polkit installed currently is 0.105:

$ pkaction --version
pkaction version 0.105

5.  I added all users to the users group (although I do not think this is essential):

$ sudo usermod -a -G users fitzcarraldo
$ sudo usermod -a -G users molly
$ sudo usermod -a -G users aquilino
$ sudo usermod -a -G users cholo
$ sudo usermod -a -G users paul

6.  I made sure the XScreenSaver settings for each user are as follows:

XScreenSaver (‘Preferences’ > ‘Screensaver’)

The ‘Display Modes’ tab has:

  • ‘Mode: Disable Screen Saver’

The ‘Advanced’ tab has everything unticked on it except for:

7.  I made sure the Xfce Power Manager settings for each user are as follows:

Xfce Power Manager (‘Preferences’ > ‘Power Manager’)

The ‘General’ tab has:

  • When power button is pressed: Ask
  • When sleep button is pressed: Do nothing
  • When hibernate button is pressed: Do nothing


  • Show notifications is ticked
  • Show system tray icon is ticked

The ‘System’ tab has:
System power saving

  • System sleep mode: Suspend
  • When inactive for 15 Minutes (You can make the number of minutes different for each user, if you want.)

The ‘Display’ tab has:
Display power management settings

  • ‘Handle display power management’ is ticked
  • Blank after: 5 Minutes
  • Put to sleep after: Never
  • Switch off after: Never

The ‘Security’ tab has:
Light Locker

  • Automatically lock the session: Never
  • Delay locking after screensaver for: ‘1 Seconds’ is greyed out
  • ‘Lock screen when system is going for sleep’ is not ticked

8.  I made sure the ‘Default Applications for LXSession’ settings for each user are as follows:

Select ‘Preferences’ > ‘Default Applications for LXSession’, click on ‘Autostart’ and untick ‘XScreenSaver’ if it is ticked. ‘Power Manager’ and ‘Screen Locker’ should already be ticked, so tick them if they are not. I left ‘PolicyKit Handler’ and ‘PolicyKit Authentication Agent’ unticked (Lubuntu 17.10 uses Polkit, the successor to PolicyKit).

9.  Although Lubuntu 17.10 does not use GNOME, I found that gsettings is installed. I did the following just in case, although I believe it is irrelevant in this particular case:

$ gsettings --version
$ gsettings set org.gnome.desktop.screensaver ubuntu-lock-on-suspend 'false'
$ gsettings get org.gnome.desktop.screensaver ubuntu-lock-on-suspend
$ gsettings set org.gnome.desktop.screensaver lock-enabled 'false'
$ gsettings get org.gnome.desktop.screensaver lock-enabled


After doing all the above, upon resuming from Suspend-to-RAM on most, but not all, occasions it is now possible to select any username on the LightDM GTK+ Greeter screen, enter that user’s password and successfully display the user’s Desktop. The LightDM GTK+ Greeter screen no longer hangs/freezes every time.

When more than one user is logged in (i.e. there is more than one session), the PC will suspend automatically if there is no user activity in a particular session during the configured timeout period for that session. Pressing a key on the USB keyboard will then wake the PC and display the LightDM GTK+ Greeter screen. The desired username can then be selected and the corresponding password entered. The following is an example of the sort of thing that can happen:

  • User fitzcarraldo (timeout configured as 30 minutes) logs in to his account at 09:00 and uses the PC until he locks his session manually (Ctrl+Alt+L) at 09:11.
  • User paul (timeout configured as 15 minutes) logs in to his account at 09:15 and uses the PC until he locks his session manually at 09:23.
  • User molly (timeout configured as 45 minutes) logs in to her account at 09:25 and uses the PC for several hours.
  • At 09:38, while user molly is using the PC, the PC automatically suspends to RAM (15 minutes after user paul stopped using his session). User molly has to wake the PC from suspension. Nothing is lost.
  • At 09:41, while user molly is using the PC, the PC automatically suspends to RAM (30 minutes after user fitzcarraldo stopped using his session). User molly has to wake the PC from suspension. Nothing is lost.

To avoid scenarios such as the above, if a user does not need the session any longer it is better to log out rather than leave the session in existence.

Syncing browser bookmarks between browsers and machines in Linux

I use several computers and various browsers (predominantly Firefox, Chrome and Chromium) and was fed up with bookmarking a site on one machine and later not finding it on another machine. For quite some time I had therefore been looking for a simple way of synchronising browser bookmarks across all my machines and browsers, and I finally found one. Below I explain what I did.

I wanted to avoid storing my bookmarks on a third-party company’s server, so that ruled out tools such as Xmarks, EverSync, Google Bookmarks and the like. I wanted the bookmark database to reside on one of my own servers that is already accessible securely via the Internet. Apparently Xmarks optionally does enable you to use your own server providing you use only Firefox, but I use various browsers (Firefox is the default browser on my main laptop whereas Chrome is the default browser on my backup laptop, for example). Furthermore, I prefer to use open-source solutions whenever possible.

Although I was looking for a GUI solution, it turns out that the command-line bookmark manager Buku does a good job in a drop-down terminal such as Yakuake, Guake or Tilda. Buku is quite powerful, yet simple to use. It is certainly practical to use in a drop-down terminal (I’m currently using it with Yakuake in KDE, and with Tilda in LXDE). Not only can you click on links to open pages in the default browser, you can also easily configure your desktop environment to use a keyboard shortcut to bookmark directly from the browser window (see the instructions in the Buku Wiki for details).

Of course, if you only want to use Buku as a local bookmark manager on a machine, you can just install it and use it solely on that machine.

It is not difficult to set up a centralised Buku database that is then synchronised with any machine on which Buku is installed. If you do not have your own Cloud server (ownCloud or Nextcloud, for example), you could use Dropbox instead. The instructions are given in the Buku Wiki. Basically, I did the following to configure several machines to use Buku via the Cloud:

1. Use each browser’s bookmark manager to export the bookmarks to a file.

2. Install Buku on each machine (see ‘Installation‘ on the package’s GitHub repository page if your Linux distribution’s package manager does not offer Buku).

3. Launch Buku once on each machine to create the local database:

$ buku -p
DB file is being created at /home/fitzcarraldo/.local/share/buku/bookmarks.db.
You should encrypt it.
[ERROR] 0 records

4. On one machine, move the Buku database file (~/.local/share/buku/bookmarks.db) to a folder on the machine that is already being synced with the Cloud, then set up a symlink to it. For example:

fitzcarraldo@clevow230ss ~ $ ls -la ~/.local/share/buku/bookmarks.db
lrwxrwxrwx 1 fitzcarraldo fitzcarraldo 51 Mar 21 13:17 /home/fitzcarraldo/.local/share/buku/bookmarks.db -> /media/NTFS/Windows/ownCloud/Bookmarks/bookmarks.db

5. Allow the Cloud client on the other machines to download the bookmarks.db file into their local Cloud sync folder, then delete the local Buku database on each machine (~/.local/share/buku/bookmarks.db) and create a symlink to the Cloud-synchronised database file. For example, in addition to the symlink shown above on the machine clevow230ss, I have the following symlinks on two other machines:

fitzcarraldo@aspirexc600:~$ ls -la ~/.local/share/buku/bookmarks.db
lrwxrwxrwx 1 fitzcarraldo fitzcarraldo 42 Mar 21 16:05 /home/fitzcarraldo/.local/share/buku/bookmarks.db -> /home/fitzcarraldo/ownCloud/Bookmarks/bookmarks.db
fitzcarraldo@meshedgedx ~ $ ls -la /home/fitzcarraldo/.local/share/buku/bookmarks.db
lrwxrwxrwx 1 fitzcarraldo users 42 Mar 26 19:15 /home/fitzcarraldo/.local/share/buku/bookmarks.db -> /home/fitzcarraldo/ownCloud/Bookmarks/bookmarks.db

6. Use Buku on each machine to import the browser bookmark files that you created in Step 1. See the Buku documentation for the command. You can find documentation and a demo video on the above-mentioned GitHub page. The commands ‘man buku‘ and ‘buku --help‘ also list the commands. The man(ual) page also contains several examples to help you.

7. Use Buku as normal on each machine. You will be able to search the synchronised database, add bookmarks and edit them (title, URL, comment and tags), delete bookmarks, print bookmarks, click on links to view the pages in the default browser, and so on.

Looking through a flat list of bookmarks in a terminal window to find something is not as fast as in a GUI but, overall, Buku is a decent bookmark manager and its options are easy to learn and use. Buku’s comprehensive search options of course help to find bookmarks, but it is still not quite as ergonomic as a GUI bookmark manager in my opinion. The ability to have multiple tags in Buku does help, as you can search for either any or all tags. In a browser’s bookmark manager I would copy the same bookmark into different folders if the Web page covers multiple topics.

In summary, Buku is a viable bookmark manager and I like it. It is extremely easy to configure for use with a Cloud server, and I have set it up to synchronise bookmarks on all my machines. I have already imported into Buku the 1,300+ bookmarks from the various browsers on my machines, and deleted the bookmarks in those browsers, so I am using Buku in earnest. I just kept a few of the most-used bookmarks on the browser’s Bookmarks Toolbar, but I’m using Buku on my machines for all the other bookmarks.

If I do have to use a third-party machine running Windows or Linux without Buku installed, I would not be able to access my bookmarks from my Cloud server. To partially get around that, I created a cron job for my user account on each of my machines to periodically run Buku and print the bookmarks to a text file synced on my Cloud server. That way I can at least search through the text file remotely via the Cloud’s Web browser interface (or via WebDAV or via OpenVPN) if I cannot find the Web page I want in a search engine on the third-party machine.

fitzcarraldo@clevow230ss ~ $ crontab -l | grep -v \#
6,26,46 * * * * rm /media/NTFS/Windows/ownCloud/Bookmarks/*.txt; sleep 30s && /usr/bin/buku -p --nc > /media/NTFS/Windows/ownCloud/Bookmarks/Buku_bookmarks_backup.txt
fitzcarraldo@aspirexc600:~$ crontab -l | grep -v \#
1,21,41 * * * * rm /home/fitzcarraldo/ownCloud/Bookmarks/*.txt; sleep 30s && /usr/local/bin/buku -p --nc > /home/fitzcarraldo/ownCloud/Bookmarks/Buku_bookmarks_backup.txt
fitzcarraldo@meshedgedx ~ $ crontab -l | grep -v \#
11,31,51 * * * * rm /home/fitzcarraldo/ownCloud/Bookmarks/*.txt; sleep 30s && /usr/bin/buku -p --nc > /home/fitzcarraldo/ownCloud/Bookmarks/Buku_bookmarks_backup.txt

Below is a small taste of searching the bookmark database using Buku on any of my machines. Output is colour-coded (user-configurable), and links are clickable in a terminal window. You can search for any keyword(s), all keywords, sub-strings, just a tag or tags, regular expression matches, and so on. You can make titles immutable (read-only) if you want, or allow Buku to update them with the title from the Web site page. There is even a command that will check and list broken links. I will leave you to study the Buku documentation.

fitzcarraldo@aspirexc600:~$ buku -S Brazil samba
1. Kaká e Mário Monteiro são os novos carnavalescos da Imperatriz Leopoldinense [159]
   +  Notícias sobre Carnaval 2016, escolas de samba, desfiles do Grupo Especial, Série A, ensaios técnicos, enredos, carnavalescos, bateria, mestre-sala, porta-bandeira, samba. Mangueira, Unidos da Tijuca, Vila Isabel, Beija-Flor, Grande Rio, Imperatriz, Mocidade, Portela, Salgueiro, União da Ilha, Viradouro, São Clemente, Porto da Pedra, Império da Tijuca, Império Serrano, Estácio de Sá, Caprichosos de Pilares, Tradição, Cubango, Em Cima da Hora, Inocentes de Belford Roxo, Alegria da Zona Sul, Unidos de Padre Miguel, Unidos de Bangu, Renascer de Jacarepaguá, Acadêmicos da Rocinha, Acadêmicos de Santa Cruz, Paraíso de Tuiuti, União de Jacarepaguá, União do Parque Curicica.
   # brazil,carnaval

2. Samba do Tuiuti 2018  Versão Acústica - YouTube [1270]
   # brazil,carnaval,music,samba,video

buku (? for help) q

In this post I have only scratched the surface of what Buku can do. For example, a simple Buku command will encrypt (AES256) the bookmark database so you can prevent others viewing your bookmarks after you have finished searching the database, should you decide to store the database on a third-party Cloud server such as Dropbox. The search and editing tools are comprehensive yet straightforward, and you will quickly learn how to use them. I take my hat off to its developer, Arun Prakash Jana from Bangalore, India. He and the other contributors to Buku have done a great job, and I recommend you give Buku a try.

Gentoo Linux: A work-around to be able to Resume from Suspend to RAM when using the NVIDIA closed-source driver

My Clevo W230SS laptop has NVIDIA Optimus graphics hardware (NVIDIA GPU plus Intel IGP). I do not use Bumblebee, preferring to switch between the Intel video driver and the NVIDIA closed-source driver myself (see Switching between Intel and NVIDIA graphics processors on a laptop with NVIDIA Optimus hardware running Gentoo Linux). The laptop can suspend to RAM and resume perfectly when using the Intel video driver (but see Stopping my laptop spontaneously resuming immediately after Suspend to RAM, which is applicable whatever the GPU or IGP).

In order to be able to resume properly from Suspend-to-RAM when using the NVIDIA driver, the laptop needs to disable compositing before suspending, then re-enable compositing after resuming. For how I achieve that, see under Problem 2 in the third link above. If this is not done, the graphics on the Desktop are corrupted after resuming.

However, recently when using the NVIDIA driver and KDE Plasma 5 (I am currently using nvidia-drivers-387.22 and plasma-meta-5.11.5), when resuming from suspension the monitor would briefly display the LightDM wallpaper (I use different wallpapers for the display manager and the lock screen, so I know it was not the KDE lock screen) followed by a blank screen with a mouse pointer (which I could move normally). More recently, in between displaying the display manager’s wallpaper and the blank screen, the monitor would briefly display an earlier image of the Desktop just before the laptop suspended.

Now, I could simply leave the laptop configured to use the Intel driver. However, sometimes I need to use a CAD application and the performance is better when using the NVIDIA GPU.

There are umpteen posts on the Web about this problem, and the root cause seems to be the closed-source NVIDIA driver. I have seen the KDE lock screen mentioned in some posts as the culprit, so I disabled the lock screen (‘System Settings’ > ‘Desktop Behaviour’ > ‘Screen Locking’) but that did not solve the problem.

I put up with this for several weeks in the hope that the next release of the NVIDIA driver would fix the problem. If I suspended to RAM while the laptop was using the NVIDIA driver, I was able to resume and get to a working Desktop – albeit without the open windows and applications that had been running before suspending – by pressing Ctrl+Alt+F1 to get to TTY1, logging in as the root user and entering the command ‘/etc/init.d/xdm restart‘. However, the final straw was in a meeting a couple of weeks ago when I wanted to resume the laptop and show a worksheet to someone. The laptop monitor of course displayed a blank screen with a mouse pointer, and it took me a couple of minutes to restart the display manager, login to KDE Plasma 5 and open the spreadsheet again. So this week I decided to look into the problem to see if I could at least find a work-around that would enable the laptop to resume without needing to restart X Windows and login to Plasma 5 each time.

I created a Bash script in /etc/pm/sleep.d/ to unload the NVIDIA modules before suspending to RAM and to re-load them when resuming, but that did not solve the problem either.

I switched the rendering background from OpenGL 2.0 to OpenGL 3.1 (‘System Settings’ > ‘Display and Monitor’ > ‘Compositor’), but that did not work either. I switched the rendering backend to XRender, and that did enable the laptop to resume from suspend successfully with the NVIDIA driver, but I do not want to use that work-around. Firstly, with software rendering there is a performance hit, and, secondly, there was no KDE Desktop Cube when using XRender instead of OpenGL. I use the Desktop Cube when working, as I often have a lot of windows open on each virtual desktop (cube side), and I find it easier to use the cube than a flat UI.

Eventually I found that, after resuming, if I pressed Ctrl+Alt+F1 to get to a virtual console, logged into my user account, entered the command ‘DISPLAY=:0 /usr/bin/kwin_x11 --resume‘ and then pressed Ctrl+Alt+F7 to get back to TTY7, my Desktop would appear on TTY7. Even so, I noticed on TTY1 that the following error messages were displayed when I ran that command:

kwin_core: OpenGL 2 compositing setup failed
kwin_core: Failed to initialize compositing, compositing disabled

Anyway, the Plasma 5 Desktop was displayed on TTY7, and with the windows that were open when I suspended the laptop, so restarting KWin would at least be a viable work-around until NVIDIA fix their video driver.

I incoporated the command in my script /etc/pm/sleep.d/02-toggle-compositing like so:

# Turn off compositing on hibernate or suspend
# Turn on compositing on thaw or resume

export XAUTHORITY="$userhome/.Xauthority"
export DISPLAY=":0"

case "$1" in
          su $username -c "qdbus org.kde.KWin /Compositor suspend" &
          su $username -c "qdbus org.kde.KWin /Compositor resume" &
          su $username -c "/usr/bin/kwin_x11 --replace" &
          exit $NA

It is an ugly hack, but at least now the laptop can resume properly from Suspend-to-RAM while the NVIDIA driver is being used.

Perhaps Linus Torvalds was correct. I will try to avoid NVIDIA hardware when I replace my current laptop.

Prevent Lubuntu 17.10 from leaving an external HDD mounted incorrectly for other users

My family’s PC running Lubuntu 17.10 has an external USB HDD connected permanently. There are several user accounts on this machine, i.e. it is a single-seat, multi-user installation. If a user does not unmount this external HDD before logging out, it is still mounted with the privileges of the previous user when another user logs in. If the current user clicks on the media unmount symbol (⏏) in the PCManFM File Manager, LXDE prompts the user to enter the previous user’s password. So I wanted to configure the OS to unmount the external HDD when each user logs out or when another user selects ‘Switch User’. The way I did that was to use the LightDM display manager to unmount the external drive at the end of a session, as explained below. Then the Udisks daemon will mount the drive correctly for any user who either logs in or switches back to his/her session.

Lubuntu 17.10 as installed has an empty directory /etc/lightdm/lightdm.conf.d/ so I created two files in that directory:

$ ls -la /etc/lightdm/lightdm.conf.d/
total 16
drwxr-xr-x 2 root root 4096 Jan  1 06:18 .
drwxr-xr-x 4 root root 4096 Jan  1 05:11 ..
-rw-r--r-- 1 root root   89 Jan  1 06:18 10_lubuntu.conf
-rwxr-xr-x 1 root root   80 Jan  1 05:55
$ cat /etc/lightdm/lightdm.conf.d/10_lubuntu.conf
$ cat /etc/lightdm/lightdm.conf.d/ 
udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015

where ‘C6576A087368B015‘ is the UUID of the external USB HDD as found from the blkid command:

$ sudo blkid | grep "FREECOM HDD"
/dev/sdb1: LABEL="FREECOM HDD" UUID="C6576A087368B015" TYPE="ntfs" PARTUUID="0024db7f-32"

Don’t forget to make the Bash script executable. Then reboot to enable the functionality. From now on the external HDD will be correctly mounted for each user who logs in to his/her account.

Update (Monday, 9 July 2018): Since I wrote the above post I upgraded Lubuntu to 18.04 and I recently noticed the following problems resulting from the above-mentioned modifications:

A. The following error message in the LightDM log file /var/log/lightdm/lightdm.log:

[SeatDefaults] is now called [Seat:*], please update this configuration

So I changed the contents of the file /etc/lightdm/lightdm.conf.d/10_lubuntu.conf from:




B. The following error message in the LightDM log file /var/log/lightdm/lightdm.log when the USB external HDD happened to not be mounted at the time:

DEBUG: Launching process 8569: /etc/lightdm/lightdm.conf.d/
DEBUG: Process 8569 terminated with signal 11

So I changed the contents of my Bash script /etc/lightdm/lightdm.conf.d/ from:

udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015


STATUS=`mount | grep $(readlink -f /dev/disk/by-uuid/C6576A087368B015 )`
if [[ ! -z $STATUS ]]; then
    udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015
exit 0