Removing qtwebengine from a Gentoo Linux installation

At the beginning of March I updated the world set in Gentoo Testing (~amd64) running the KDE suite (Plasma, Frameworks and Applications) on my secondary laptop, an eleven-year-old Compal NBLB2. It has a first-generation Core i7 CPU and the maximum amount of RAM that can be installed in that model (8 GB).

root # uname -a
Linux meshedgedx 5.0.11-gentoo #1 SMP Fri Jun 7 15:33:06 BST 2019 x86_64 Intel(R) Core(TM) i7 CPU Q 720 @ 1.60GHz GenuineIntel GNU/Linux

Gentoo Linux being a source-based distribution, updates to the largest packages take hours to build on older machines. Actually, some packages can take hours to build on newer machines too. On this older laptop I therefore merge the www-client/firefox-bin binary package instead of the www-client/firefox source-code package, and have installed Microsoft Office 2007 running in WINE instead of trying to merge the app-office/libreoffice source-code package (app-office/libreoffice-bin cannot be merged in this Testing installation because of incompatibility with the versions of installed dependencies, so it would only be a viable alternative binary package in a Stable installation).

Possibly the worst source-code package to build is dev-qt/qtwebengine. Nowadays it takes a ridiculous amount of time to build on this laptop, even with the jumbo-build USE flag set and MAKEOPTS="-j4" or even MAKEOPTS="-j1". The latest merge on the laptop took more than 14 hours:

root # genlop -t qtwebengine | tail -n 3
     Fri Mar  5 02:02:07 2021 >>> dev-qt/qtwebengine-5.15.2_p20210224
       merge time: 14 hours, 14 minutes and 7 seconds.


That is actually quite fast for that laptop; qtwebengine has sometimes taken two days to merge in the past.

What a waste of time and electricity, not to mention the unnecessary wear on the laptop (fan bearing; prolonged heat on components; etc.).

This one package is such a hassle to merge that it had me wondering if I should switch from Gentoo Linux to a binary distribution. Even on my six-year-old Compal W230SS laptop with a fourth-generation Core i7 CPU and 16 GB of RAM, qtwebengine takes circa five hours to merge. After several years putting up with this scourge of source-based Linux distributions on my secondary laptop, I had finally had enough and decided to excise the package, which did not look like an easy task with the full KDE suite installed. This is how I did it…

1. First I made sure the installation was up-to-date (see my earlier post ‘My system upgrade procedure for Gentoo Linux‘ for the steps I normally use to update all packages to their latest versions).

2. I ascertained which packages depended on qtwebengine:

root # equery depends qtwebengine
 * These packages depend on qtwebengine:
kde-apps/kaccounts-providers-20.12.2 (>=dev-qt/qtwebengine-5.15.2:5)
kde-apps/kalgebra-20.12.2 (>=dev-qt/qtwebengine-5.15.2:5[widgets])
kde-apps/kdenlive-20.12.2 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
kde-apps/kimagemapeditor-20.12.2 (>=dev-qt/qtwebengine-5.15.2:5[widgets])
kde-apps/ktp-text-ui-20.12.2 (>=dev-qt/qtwebengine-5.15.2:5[widgets])
kde-apps/marble-20.12.2 (webengine ? >=dev-qt/qtwebengine-5.15.2:5[widgets])
kde-apps/parley-20.12.2 (>=dev-qt/qtwebengine-5.15.2:5[widgets])
kde-plasma/kdeplasma-addons-5.21.1 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
kde-plasma/libksysguard-5.21.1 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
net-libs/signon-ui-0.15_p20171022-r1 (dev-qt/qtwebengine:5)
net-p2p/ktorrent-20.12.2 (rss ? >=dev-qt/qtwebengine-5.15.2:5)
                         (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
www-client/falkon-3.1.0-r1 (>=dev-qt/qtwebengine-5.12.3:5[widgets])

3. I disabled the USE flag ‘webengine‘ globally:

root # nano /etc/portage/make.conf # Add -webengine to the list of USE flags

4. I merged the world set in order to incorporate the USE flag change:

root # emerge -uvDN @world

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild   R    ] kde-apps/marble-20.12.2:5/20.12::gentoo  USE="dbus geolocation kde nls pbf phonon -aprs -debug -designer -gps -handbook -shapefile -test -webengine*" 0 KiB
[ebuild   R    ] kde-apps/kdeedu-meta-20.12.2:5::gentoo  USE="-webengine*" 0 KiB
[ebuild   R    ] kde-apps/kdecore-meta-20.12.2:5::gentoo  USE="share thumbnail -handbook -webengine*" 0 KiB
[ebuild   R    ] net-p2p/ktorrent-20.12.2:5::gentoo  USE="bwscheduler downloadorder infowidget ipfilter kross logviewer magnetgenerator mediaplayer rss scanfolder shutdown stats upnp zeroconf -debug -handbook -test -webengine*" 0 KiB
[ebuild   R    ] kde-apps/kdenetwork-meta-20.12.2:5::gentoo  USE="bittorrent -dropbox -webengine*" 0 KiB
[ebuild   R    ] kde-apps/kdeutils-meta-20.12.2:5::gentoo  USE="cups rar -7zip -floppy -gpg -lrz -webengine*" 0 KiB

Total: 6 packages (6 reinstalls), Size of downloads: 0 KiB

>>> Verifying ebuild manifests
>>> Emerging (1 of 6) kde-apps/marble-20.12.2::gentoo
>>> Emerging (2 of 6) kde-apps/kdecore-meta-20.12.2::gentoo
>>> Emerging (3 of 6) net-p2p/ktorrent-20.12.2::gentoo
>>> Emerging (4 of 6) kde-apps/kdeutils-meta-20.12.2::gentoo
>>> Installing (2 of 6) kde-apps/kdecore-meta-20.12.2::gentoo
>>> Installing (4 of 6) kde-apps/kdeutils-meta-20.12.2::gentoo
>>> Installing (3 of 6) net-p2p/ktorrent-20.12.2::gentoo
>>> Emerging (5 of 6) kde-apps/kdenetwork-meta-20.12.2::gentoo
>>> Installing (5 of 6) kde-apps/kdenetwork-meta-20.12.2::gentoo
>>> Installing (1 of 6) kde-apps/marble-20.12.2::gentoo
>>> Emerging (6 of 6) kde-apps/kdeedu-meta-20.12.2::gentoo
>>> Installing (6 of 6) kde-apps/kdeedu-meta-20.12.2::gentoo
>>> Jobs: 6 of 6 complete                           Load avg: 1.93, 3.62, 3.86
>>> Auto-cleaning packages...

>>> No outdated packages were found on your system.

 * GNU info directory index is up-to-date.
 * After world updates, it is important to remove obsolete packages with
 * emerge --depclean. Refer to `man emerge` for more information.

5. I uninstalled packages that were no longer required by any other packages and also not required by me (I do not use the Falkon browser, Telepathy and KAlgebra, to give a few examples, and so did not mind various specific packages being removed):

root # emerge --ask --depclean

 * Always study the list of packages to be cleaned for any obvious
 * mistakes. Packages that are part of the world set will always
 * be kept.  They can be manually added to this set with
 * `emerge --noreplace `.  Packages that are listed in
 * package.provided (see portage(5)) will be removed by
 * depclean, even if they are part of the world set.
 * 
 * As a safety measure, depclean will not remove any packages
 * unless *all* required dependencies have been resolved.  As a
 * consequence of this, it often becomes necessary to run 
 * `emerge --update --newuse --deep @world` prior to depclean.

Calculating dependencies... done!
>>> Calculating removal order...

>>> These are the packages that would be unmerged:                                                                                                                                                                                                

 kde-apps/parley
    selected: 20.12.2 
   protected: none 
     omitted: none 

 www-client/falkon
    selected: 3.1.0-r1 
   protected: none 
     omitted: none 

 kde-apps/kimagemapeditor
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/plasma-telepathy-meta
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/kalgebra
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-kded-module
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-desktop-applets
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-accounts-kcm
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-send-file
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-approver
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-auth-handler
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-contact-runner
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-text-ui
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/signon-kwallet-extension
    selected: 20.12.2 
   protected: none 
     omitted: none 

 net-im/telepathy-connection-managers
    selected: 2-r2 
   protected: none 
     omitted: none 

 kde-apps/ktp-filetransfer-handler
    selected: 20.12.2 
   protected: none 
     omitted: none 

 kde-apps/ktp-contact-list
    selected: 20.12.2 
   protected: none 
     omitted: none 

 net-irc/telepathy-idle
    selected: 0.2.0-r3 
   protected: none 
     omitted: none 

 net-voip/telepathy-salut
    selected: 0.8.1-r3 
   protected: none 
     omitted: none 

 net-voip/telepathy-gabble
    selected: 0.18.4-r2 
   protected: none 
     omitted: none 

 kde-apps/ktp-common-internals
    selected: 20.12.2 
   protected: none 
     omitted: none 

 net-libs/telepathy-accounts-signon
    selected: 2.1 
   protected: none 
     omitted: none 

 net-libs/libnice
    selected: 0.1.15 
   protected: none 
     omitted: none 

 net-libs/telepathy-logger-qt
    selected: 17.09.0 
   protected: none 
     omitted: none 

 net-im/telepathy-logger
    selected: 0.8.2-r1 
   protected: none 
     omitted: none 

 net-libs/gupnp-igd
    selected: 0.2.5-r10 
   protected: none 
     omitted: none 

 net-libs/libsignon-glib
    selected: 2.1 
   protected: none 
     omitted: none 

 net-libs/telepathy-qt
    selected: 0.9.8 
   protected: none 
     omitted: none 

 net-libs/gupnp
    selected: 1.2.4 
   protected: none 
     omitted: none 

 net-libs/gssdp
    selected: 1.2.3 
   protected: none 
     omitted: none 

 net-libs/libsoup
    selected: 2.70.0 
   protected: none 
     omitted: none 

 net-libs/libpsl
    selected: 0.21.1 
   protected: none 
     omitted: none 

 net-libs/glib-networking
    selected: 2.66.0 
   protected: none 
     omitted: none 

 net-im/telepathy-mission-control
    selected: 5.16.5 
   protected: none 
     omitted: none 

 net-libs/telepathy-glib
    selected: 0.24.1-r1 
   protected: none 
     omitted: none 

All selected packages: =kde-apps/ktp-desktop-applets-20.12.2 =kde-apps/ktp-contact-runner-20.12.2 =kde-apps/ktp-contact-list-20.12.2 =net-libs/telepathy-accounts-signon-2.1 =net-libs/telepathy-glib-0.24.1-r1 =net-voip/telepathy-salut-0.8.1-r3 =kde-apps/ktp-text-ui-20.12.2 =net-libs/libsignon-glib-2.1 =net-im/telepathy-connection-managers-2-r2 =kde-apps/ktp-accounts-kcm-20.12.2 =kde-apps/kimagemapeditor-20.12.2 =kde-apps/ktp-common-internals-20.12.2 =kde-apps/parley-20.12.2 =net-libs/libnice-0.1.15 =net-libs/libsoup-2.70.0 =kde-apps/ktp-auth-handler-20.12.2 =net-libs/gssdp-1.2.3 =net-irc/telepathy-idle-0.2.0-r3 =net-libs/libpsl-0.21.1 =kde-apps/kalgebra-20.12.2 =net-libs/gupnp-igd-0.2.5-r10 =kde-apps/ktp-filetransfer-handler-20.12.2 =kde-apps/ktp-send-file-20.12.2 =net-libs/gupnp-1.2.4 =kde-apps/ktp-kded-module-20.12.2 =net-im/telepathy-mission-control-5.16.5 =kde-apps/plasma-telepathy-meta-20.12.2 =net-voip/telepathy-gabble-0.18.4-r2 =net-im/telepathy-logger-0.8.2-r1 =kde-apps/signon-kwallet-extension-20.12.2 =net-libs/telepathy-logger-qt-17.09.0 =net-libs/telepathy-qt-0.9.8 =net-libs/glib-networking-2.66.0 =kde-apps/ktp-approver-20.12.2 =www-client/falkon-3.1.0-r1

>>> 'Selected' packages are slated for removal.
>>> 'Protected' and 'omitted' packages will not be removed.

Would you like to unmerge these packages? [Yes/No] Yes 
>>> Waiting 5 seconds before starting...
>>> (Control-C to abort)...
>>> Unmerging in: 5 4 3 2 1
>>> Unmerging (1 of 35) kde-apps/parley-20.12.2...
>>> Unmerging (2 of 35) www-client/falkon-3.1.0-r1...
>>> Unmerging (3 of 35) kde-apps/kimagemapeditor-20.12.2...
>>> Unmerging (4 of 35) kde-apps/plasma-telepathy-meta-20.12.2...
>>> Unmerging (5 of 35) kde-apps/kalgebra-20.12.2...
>>> Unmerging (6 of 35) kde-apps/ktp-kded-module-20.12.2...
>>> Unmerging (7 of 35) kde-apps/ktp-desktop-applets-20.12.2...
>>> Unmerging (8 of 35) kde-apps/ktp-accounts-kcm-20.12.2...
>>> Unmerging (9 of 35) kde-apps/ktp-send-file-20.12.2...
>>> Unmerging (10 of 35) kde-apps/ktp-approver-20.12.2...
>>> Unmerging (11 of 35) kde-apps/ktp-auth-handler-20.12.2...
>>> Unmerging (12 of 35) kde-apps/ktp-contact-runner-20.12.2...
>>> Unmerging (13 of 35) kde-apps/ktp-text-ui-20.12.2...
>>> Unmerging (14 of 35) kde-apps/signon-kwallet-extension-20.12.2...
>>> Unmerging (15 of 35) net-im/telepathy-connection-managers-2-r2...
>>> Unmerging (16 of 35) kde-apps/ktp-filetransfer-handler-20.12.2...
>>> Unmerging (17 of 35) kde-apps/ktp-contact-list-20.12.2...
>>> Unmerging (18 of 35) net-irc/telepathy-idle-0.2.0-r3...
>>> Unmerging (19 of 35) net-voip/telepathy-salut-0.8.1-r3...
>>> Unmerging (20 of 35) net-voip/telepathy-gabble-0.18.4-r2...
>>> Unmerging (21 of 35) kde-apps/ktp-common-internals-20.12.2...
>>> Unmerging (22 of 35) net-libs/telepathy-accounts-signon-2.1...
>>> Unmerging (23 of 35) net-libs/libnice-0.1.15...
>>> Unmerging (24 of 35) net-libs/telepathy-logger-qt-17.09.0...
>>> Unmerging (25 of 35) net-im/telepathy-logger-0.8.2-r1...
>>> Unmerging (26 of 35) net-libs/gupnp-igd-0.2.5-r10...
>>> Unmerging (27 of 35) net-libs/libsignon-glib-2.1...
>>> Unmerging (28 of 35) net-libs/telepathy-qt-0.9.8...
>>> Unmerging (29 of 35) net-libs/gupnp-1.2.4...
>>> Unmerging (30 of 35) net-libs/gssdp-1.2.3...
>>> Unmerging (31 of 35) net-libs/libsoup-2.70.0...
>>> Unmerging (32 of 35) net-libs/libpsl-0.21.1...
>>> Unmerging (33 of 35) net-libs/glib-networking-2.66.0...
>>> Unmerging (34 of 35) net-im/telepathy-mission-control-5.16.5...
>>> Unmerging (35 of 35) net-libs/telepathy-glib-0.24.1-r1...
Packages installed:   1651
Packages in world:    329
Packages in system:   43
Required packages:    1651
Number removed:       35

 * GNU info directory index is up-to-date.

Notice that the package qtwebengine had not been removed, so something still depended on it.

6. I checked if there were any packages still installed with a dependency on qtwebengine:

root # equery depends qtwebengine
 * These packages depend on qtwebengine:
kde-apps/kaccounts-providers-20.12.2 (>=dev-qt/qtwebengine-5.15.2:5)
kde-apps/kdenlive-20.12.2 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
kde-apps/marble-20.12.2 (webengine ? >=dev-qt/qtwebengine-5.15.2:5[widgets])
kde-plasma/kdeplasma-addons-5.21.1 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
kde-plasma/libksysguard-5.21.1 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
net-libs/signon-ui-0.15_p20171022-r1 (dev-qt/qtwebengine:5)
net-p2p/ktorrent-20.12.2 (rss ? >=dev-qt/qtwebengine-5.15.2:5)
                         (webengine ? >=dev-qt/qtwebengine-5.15.2:5)

As can be seen from the above output, the only remaining installed packages that ‘hard-depended’ on the ‘webengine‘ USE flag were kde-apps/kaccounts-providers-20.12.2 and net-libs/signon-ui-0.15_p20171022-r1.

Additionally, the package net-p2p/ktorrent-20.12.2 still depended on qtwebengine because the rss USE flag was enabled. So I added the line ‘net-p2p/ktorrent -rss‘ to the file /etc/portage/package.use/package.use and re-merged net-p2p/ktorrent. Actually, I re-merged the following packages just in case they needed to be rebuilt, although in retrospect I believe that was unnecessary:

     Fri Mar  5 05:37:26 2021 >>> kde-apps/kdecore-meta-20.12.2
     Fri Mar  5 05:37:55 2021 >>> kde-apps/kdeutils-meta-20.12.2
     Fri Mar  5 05:45:49 2021 >>> net-p2p/ktorrent-20.12.2
     Fri Mar  5 05:46:49 2021 >>> kde-apps/kdenetwork-meta-20.12.2
     Fri Mar  5 05:57:41 2021 >>> kde-apps/marble-20.12.2
     Fri Mar  5 05:58:15 2021 >>> kde-apps/kdeedu-meta-20.12.2

7. By now another day had dawned, so I checked if new versions of the ebuilds for any KDE packages had been uploaded to the Portage repositories:

root # emaint sync -a
root # eix-update && updatedb

8. I rebooted the laptop and checked which packages still depended on qtwebengine. It turned out that only the two packages with a hard-dependency on qtwebengine were still preventing me from removing it:

root # equery depends qtwebengine
 * These packages depend on qtwebengine:
kde-apps/kaccounts-providers-20.12.2 (>=dev-qt/qtwebengine-5.15.2:5)
net-libs/signon-ui-0.15_p20171022-r1 (dev-qt/qtwebengine:5)

9. I checked if any packages depended on those two packages:

root # equery depends kaccounts-providers
 * These packages depend on kaccounts-providers:
kde-misc/kio-gdrive-20.12.2 (>=kde-apps/kaccounts-providers-20.12.2:5)
# equery depends kio-gdrive
 * These packages depend on kio-gdrive:
kde-apps/kdenetwork-meta-20.12.2 (>=kde-misc/kio-gdrive-20.12.2:5)
root # equery depends signon-ui
 * These packages depend on signon-ui:
kde-apps/kaccounts-providers-20.12.2 (net-libs/signon-ui)

So kdenetwork-meta hard-depends on kio-gdrive, which does not make much sense, really, given that not all KDE users have a Google Drive account and those users therefore do not need the kio-gdrive package to be installed.

10. The contents of the kdenetwork-meta-20.12.3 ebuild look like this:

root # cat /usr/portage/kde-apps/kdenetwork-meta/kdenetwork-meta-20.12.3.ebuild
# Copyright 1999-2021 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

EAPI=7

DESCRIPTION="kdenetwork - merge this to pull in all kdenetwork-derived packages"
HOMEPAGE="https://kde.org/"

LICENSE="metapackage"
SLOT="5"
KEYWORDS="~amd64 ~arm64 ~ppc64 ~x86"
IUSE="+bittorrent dropbox +webengine"

RDEPEND="
        >=kde-apps/kdenetwork-filesharing-${PV}:${SLOT}
        >=kde-apps/kget-${PV}:${SLOT}
        >=kde-apps/kopete-${PV}:${SLOT}
        >=kde-apps/krdc-${PV}:${SLOT}
        >=kde-apps/krfb-${PV}:${SLOT}
        >=kde-apps/zeroconf-ioslave-${PV}:${SLOT}
        >=kde-misc/kdeconnect-${PV}:${SLOT}
        >=kde-misc/kio-gdrive-${PV}:${SLOT}
        >=net-irc/konversation-${PV}:${SLOT}
        bittorrent? (
                >=net-libs/libktorrent-${PV}:${SLOT}
                >=net-p2p/ktorrent-${PV}:${SLOT}
        )
        dropbox? ( >=kde-apps/dolphin-plugins-dropbox-${PV}:${SLOT} )
"

so I created an ebuild for kdenetwork-meta-20.12.3 in my local overlay with the dependency on kio-gdrive removed:

root # mkdir -p /usr/local/portage/kde-apps/kdenetwork-meta
root # cd /usr/local/portage/kde-apps/kdenetwork-meta
root # cp /usr/portage/kde-apps/kdenetwork-meta/kdenetwork-meta-20.12.3.ebuild .
root # nano kdenetwork-meta-20.12.3.ebuild # Delete the line containing ">=kde-misc/kio-gdrive-${PV}:${SLOT}"
root # ebuild kdenetwork-meta-20.12.3.ebuild manifest
>>> Creating Manifest for /usr/local/portage/kde-apps/kdenetwork-meta
root # # eix-update && updatedb

11. I re-merged the world set in order to update all KDE packages that now had a newer ebuild version:

root # emerge -uvDN @world

12. I rechecked the three packages that had depended on qtwebengine:

root # equery depends signon-ui
 * These packages depend on signon-ui:
kde-apps/kaccounts-providers-20.12.3 (net-libs/signon-ui)
root # equery depends kaccounts-providers
 * These packages depend on kaccounts-providers:
kde-misc/kio-gdrive-20.12.3 (kaccounts ? >=kde-apps/kaccounts-providers-20.08.3:5)
root # equery depends kio-gdrive
 * These packages depend on kio-gdrive:
root #

As can be seen above, my modified ebuild for kdenetwork-meta-20.12.3 had indeed removed the impediment to uninstalling kio-gdrive and therefore the impediment to uninstalling kaccount-providers and signon-ui.

13. I merged my modified version of kdenetwork-meta-20.12.3:

Up to this point kde-apps/kdenetwork-meta-20.12.3 had been merged from the main Portage tree:

root # eix -I kde-apps/kdenetwork-meta
[I] kde-apps/kdenetwork-meta
     Available versions:  (5) 20.08.3-r1 (~)20.12.3 (~)20.12.3[1]
       {+bittorrent dropbox +webengine}
     Installed versions:  20.12.3(5)(15:23:08 05/03/21)(bittorrent -dropbox -webengine)
     Homepage:            https://kde.org/
     Description:         kdenetwork - merge this to pull in all kdenetwork-derived packages

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

I then merged the version from my local overlay:

root # emerge -1v kdenetwork-meta::local_overlay

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild   R    ] kde-apps/kdenetwork-meta-20.12.3:5::local_overlay [20.12.3:5::gentoo] USE="bittorrent -dropbox -webengine" 0 KiB

Total: 1 package (1 reinstall), Size of downloads: 0 KiB

>>> Verifying ebuild manifests
>>> Emerging (1 of 1) kde-apps/kdenetwork-meta-20.12.3::local_overlay
>>> Installing (1 of 1) kde-apps/kdenetwork-meta-20.12.3::local_overlay
>>> Jobs: 1 of 1 complete                           Load avg: 1.76, 0.88, 0.61
>>> Auto-cleaning packages...

>>> No outdated packages were found on your system.

 * GNU info directory index is up-to-date.
root # eix -I kde-apps/kdenetwork-meta
[I] kde-apps/kdenetwork-meta
     Available versions:  (5) 20.08.3-r1 (~)20.12.3 (~)20.12.3[1]
       {+bittorrent dropbox +webengine}
     Installed versions:  20.12.3(5)[1](16:40:43 05/03/21)(bittorrent -dropbox -webengine)
     Homepage:            https://kde.org/
     Description:         kdenetwork - merge this to pull in all kdenetwork-derived packages

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

14. I checked which packages still depended on qtwebengine:

root # equery depends qtwebengine
 * These packages depend on qtwebengine:
kde-apps/kaccounts-providers-20.12.3 (>=dev-qt/qtwebengine-5.15.2:5)
kde-apps/kdenlive-20.12.3 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
kde-apps/marble-20.12.3 (webengine ? >=dev-qt/qtwebengine-5.15.2:5[widgets])
kde-plasma/kdeplasma-addons-5.21.2 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
kde-plasma/libksysguard-5.21.2 (webengine ? >=dev-qt/qtwebengine-5.15.2:5)
net-libs/signon-ui-0.15_p20171022-r1 (dev-qt/qtwebengine:5)
net-p2p/ktorrent-20.12.3 (rss ? >=dev-qt/qtwebengine-5.15.2:5)
                         (webengine ? >=dev-qt/qtwebengine-5.15.2:5)

Eureka! kdenetwork-meta no longer depends on qtwebengine.

15. I was then able to remove qtwebengine and the remaining packages that hard-depend on it:

root # emerge --ask --depclean qtwebengine kaccounts-providers signon-ui kio-gdrive

Calculating dependencies... done!
>>> Calculating removal order...

>>> These are the packages that would be unmerged:                                                                                                                                                                                                

 kde-misc/kio-gdrive
    selected: 20.12.3 
   protected: none 
     omitted: none 

 kde-apps/kaccounts-providers
    selected: 20.12.3 
   protected: none 
     omitted: none 

 net-libs/signon-ui
    selected: 0.15_p20171022-r1 
   protected: none 
     omitted: none 

 dev-qt/qtwebengine
    selected: 5.15.2_p20210224 
   protected: none 
     omitted: none 

All selected packages: =dev-qt/qtwebengine-5.15.2_p20210224 =kde-apps/kaccounts-providers-20.12.3 =kde-misc/kio-gdrive-20.12.3 =net-libs/signon-ui-0.15_p20171022-r1

>>> 'Selected' packages are slated for removal.
>>> 'Protected' and 'omitted' packages will not be removed.

Would you like to unmerge these packages? [Yes/No] Yes
>>> Waiting 5 seconds before starting...
>>> (Control-C to abort)...
>>> Unmerging in: 5 4 3 2 1
>>> Unmerging (1 of 4) kde-misc/kio-gdrive-20.12.3...
>>> Unmerging (2 of 4) kde-apps/kaccounts-providers-20.12.3...
>>> Unmerging (3 of 4) net-libs/signon-ui-0.15_p20171022-r1...
>>> Unmerging (4 of 4) dev-qt/qtwebengine-5.15.2_p20210224...
Packages installed:   1648
Packages in world:    329
Packages in system:   43
Required packages:    1648
Number removed:       4

 * GNU info directory index is up-to-date.

\o/ \o/ \o/ \o/ No more qtwebengine in Gentoo Linux Testing (~amd64) running KDE.

Of course this was only possible because I do not need the specific packages that had been uninstalled during this entire procedure. Other people may not be in the same position.

16. I added the following lines to the file /etc/portage/package.mask/package.mask so that the packages are not pulled in automatically when merging the world set in future:

dev-qt/qtwebengine
kde-apps/kdenetwork-meta::gentoo
kde-misc/kio-gdrive
kde-apps/kaccounts-providers
net-libs/signon-ui

17. In future I will have to modify new versions of the kdenetwork-meta ebuild and add them to my local overlay. Furthermore, if other packages become dependent on qtwebengine in future and I do not require them, I will have to repeat the above steps in order to remove them (if viable). I just hope I can keep the qtwebengine package from ever being installed again.

Enabling other users to login from the xscreensaver lockscreen in Lubuntu 20.10

If Lubuntu 20.10 suspends to RAM, xscreensaver displays a lockscreen with login window when the system resumes. However, LXQt and SDDM currently do not provide a ‘Switch User’ option, so, if you are not the currently logged-in user and you do not know that user’s password, you will be stuck on the xscreensaver lockscreen. If you click on ‘New Login’ in the xscreensaver window, a message similar to the following is displayed and there is no way for a different user to login:

xscreensaver: 19:01:52: could not execute "gdmflexiserver": No such file or directory

To get around this problem so that other users can login, create the file /usr/local/bin/gdmflexiserver containing the following two lines:

#!/bin/bash
who | awk '!/root/{ cmd="/usr/bin/pkill -KILL -u " $1; system(cmd)}'

Make it executable:

$ sudo chmod +x /usr/local/bin/gdmflexiserver

Now, when the xscreensaver login window appears, if you do not know the currently logged-in user’s password you can click on the ‘New Login’ button instead and the SDDM greeter screen will be displayed so that another user can login. Note that clicking on ‘New Login’ will lose all the open windows and any running applications in the current user’s session, but at least a different user will not be prevented from logging-in and using the machine if the original user is not available to login then logout from his/her session. Of course, if the current user is still available, he/she can simply unlock the current session as usual via the xscreensaver lockscreen window.

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
Exec=light-locker

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"/>
  </property>
</channel>

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:

[SeatDefaults]
session-cleanup-script=/etc/lightdm/lightdm.conf.d/unmount_FREECOM_HDD.sh

to:

[Seat:*]
session-cleanup-script=/etc/lightdm/lightdm.conf.d/unmount_FREECOM_HDD.sh

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/unmount_FREECOM_HDD.sh
DEBUG: Process 8569 terminated with signal 11

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

#!/bin/bash
udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015

to:

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

Conclusions

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.

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

Introduction

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.

Modifications

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
/etc/xdg/autostart/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:

#!/bin/sh
case "$1" in
    pre|suspend|hibernate)
        date | tr -d '\n' >> /home/fitzcarraldo/sleep.log
        echo " going to sleep." >> /home/fitzcarraldo/sleep.log
        chvt 1
        loginctl unlock-sessions
    ;;
    post|resume|thaw)
        date | tr -d '\n' >> /home/fitzcarraldo/sleep.log
        echo " waking from sleep." >> /home/fitzcarraldo/sleep.log
        loginctl lock-sessions
        chvt 7
    ;;
    *)
        exit $NA
    ;;
esac
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 (action.id == "org.freedesktop.login1.suspend" ||
        action.id == "org.freedesktop.login1.suspend-multiple-sessions" ||
        action.id == "org.freedesktop.login1.hibernate" ||
        action.id == "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 (action.id == "org.freedesktop.login1.suspend" ||
        action.id == "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]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend;org.freedesktop.login1.suspend-multiple-sessions;org.freedesktop.login1.hibernate;org.freedesktop.login1.hibernate-multiple-sessions
ResultAny=yes
ResultInactive=yes
ResultActive=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:

[Allow suspending with lock screen]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend;org.freedesktop.login1.suspend-multiple-sessions
ResultAny=yes
ResultInactive=yes
ResultActive=yes

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

Power Manager
GDBus.Error:org.freedesktop.DBus.Error.NoReply:
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:
Buttons

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

Appearance

  • 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
2.54.1
$ gsettings set org.gnome.desktop.screensaver ubuntu-lock-on-suspend 'false'
$ gsettings get org.gnome.desktop.screensaver ubuntu-lock-on-suspend
false
$ gsettings set org.gnome.desktop.screensaver lock-enabled 'false'
$ gsettings get org.gnome.desktop.screensaver lock-enabled
false

Conclusion

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]
   > http://www.sidneyrezende.com/editoria/carnaval
   +  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]
   > https://www.youtube.com/watch?v=yUxfwAzHOeY
   # 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:

#!/bin/sh
#
# Turn off compositing on hibernate or suspend
# Turn on compositing on thaw or resume

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

case "$1" in
     suspend|hibernate)
          su $username -c "qdbus org.kde.KWin /Compositor suspend" &
     ;;
     resume|thaw)
          su $username -c "qdbus org.kde.KWin /Compositor resume" &
          su $username -c "/usr/bin/kwin_x11 --replace" &
     ;;
     *)
          exit $NA
     ;;
esac

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.

xdotool comes to the rescue

In a previous post I explained how I implemented a method for adding my current location and the local time to my e-mail signature wherever I happen to be in the World, irrespective of the time on the laptop’s hardware clock and system clock. In that post I described how I created a keyboard shortcut using the Linux application AutoKey. Unfortunately AutoKey has not been updated for several years and no longer works properly in KDE Plasma 5 on my laptops. Therefore I decided to replace it with a KDE keyboard shortcut, and this is to explain how I did it.

First create a custom shortcut in KDE:

  1. ‘System Settings’ > ‘Shortcuts’ > ‘Custom Shortcuts’
  2. ‘Edit’ > ‘New’ > ‘Global Shortcut’ > ‘Command/URL’, and name the New Action ‘Insert current time’
  3. On the Comment pane for ‘Insert current time’, add the comment ‘Insert current time at specified location’ (without the quotes)
  4. On the Trigger pane, configure the shortcut to be Ctrl+Alt+Space
  5. On the Action pane, enter the Command/URL as ‘/home/fitzcarraldo/timezone_signature_GeoNames.sh‘ (without the quotes)
  6. Click ‘Apply’

Next modify the Bash script timezone_signature_GeoNames.sh so that it contains the following (obviously change the username and path to suit):

#!/bin/bash

place=$(kdialog --title "Current Location" --inputbox "Enter your location:")

placetime=$(perl /home/fitzcarraldo/now1.pl $place)

# xdotool does not output a space in a string, so we have to extract each field from the string
# and print each field individually, separated by a space character.

city=$(echo $placetime | awk -F "|" '{print $1}')
country=$(echo $placetime | awk -F "|" '{print $2}' | sed 's/[)(]//g')
region=$(echo $placetime | awk -F "|" '{print $4}')

datetime=$(/usr/bin/zdump $region | awk -F " " '{print $2" "$3" "$4" "$5" "$6" "$7}')
dayofweek=$(echo $datetime | awk -F " " '{print $1}')
month=$(echo $datetime | awk -F " " '{print $2}')
day=$(echo $datetime | awk -F " " '{print $3}')
time=$(echo $datetime | awk -F " " '{print $4}')
year=$(echo $datetime | awk -F " " '{print $5}')
timezone=$(echo $datetime | awk -F " " '{print $6}')

activewindow=$(xdotool getactivewindow)

xdotool type --window $activewindow "Sent from:"
for oneword in $city; do
    xdotool key --window $activewindow space
    sleep 0.1s
    xdotool type --window $activewindow --delay 100 $oneword
done
xdotool key --window $activewindow comma
for oneword in $country; do
    xdotool key --window $activewindow space
    sleep 0.1s
    xdotool type --window $activewindow --delay 100 $oneword
done
xdotool key --window $activewindow Return
xdotool type --window $activewindow "Local time now: "
xdotool type --window $activewindow $dayofweek
xdotool type --window $activewindow " "
xdotool type --window $activewindow $month
xdotool type --window $activewindow " "
xdotool type --window $activewindow $day
xdotool type --window $activewindow " "
xdotool type --window $activewindow $time
xdotool type --window $activewindow " "
xdotool type --window $activewindow $year
xdotool type --window $activewindow " "
if [ ${timezone:0:1} = "-" ]; then
    timezone="UTC-"${timezone#*-}
elif [ ${timezone:0:1} = "+" ]; then
    timezone="UTC+"${timezone#*+}
fi
xdotool type --window $activewindow $timezone
xdotool type --window $activewindow " "
xdotool key --window $activewindow Return
xdotool key --window $activewindow Return
echo

The Perl script now1.pl is listed in my my earlier post. Notice that the script timezone_signature_GeoNames.sh in my earlier post was much simpler. This was because the AutoKey shortcut took care of sending the text to the currently active window. Without AutoKey, I now had to do this myself in the script timezone_signature_GeoNames.sh, and the command xdotool came to the rescue. The developer explains what xdotool does as follows:

This tool lets you simulate keyboard input and mouse activity, move and resize windows, etc. It does this using X11’s XTEST extension and other Xlib functions.

Additionally, you can search for windows and move, resize, hide, and modify window properties like the title. If your window manager supports it, you can use xdotool to switch desktops, move windows between desktops, and change the number of desktops.

So I installed xdotool via the Gentoo package manager:

# emerge xdotool
# eix xdotool
[I] x11-misc/xdotool
     Available versions:  3.20150503.1-r1^t ~3.20160805.1^t {examples}
     Installed versions:  3.20150503.1-r1^t(22:51:30 02/04/17)(-examples)
     Homepage:            http://www.semicomplete.com/projects/xdotool/
     Description:         Simulate keyboard input and mouse activity, move and resize windows

Anyway, my Bash script using xdotool works a treat with Thunderbird (and KWrite, LibreOffice Writer, etc.). I used to experience a problem with certain characters, for example a colon was printed as a semi-colon (see the xdotool bug report xdotool writes the wrong case #121), but that no longer happens in my current KDE Plasma 5 installation:

Sent from: Galeão International Airport, Brazil
Local time now: Thu Jul 6 15:11:40 2017 UTC-03

What a useful tool xdotool is!

Using the ClamAV daemon to scan files placed in my Downloads directory in Gentoo Linux

In a previous post I explained how to automatically detect files placed in my Downloads directory in Linux and scan them for viruses. The method I described in that post used clamscan, the command-line anti-virus scanner of ClamAV. Now, in addition ClamAV has a daemon (a program that runs continuously in the background), clamdscan, that you can enable. So I decided to switch to using clamdscan, as its response to downloaded files is much faster because the process waiting for new files to appear in ~/Downloads/ does not have to load clamscan from disk each time a new file arrives. Anyway, if you want to monitor a download directory in Gentoo Linux (running OpenRC) by using the ClamAV daemon — which will also download virus signature database updates automatically — then the procedure to set this up is given below.

1. Install clamav if it is not installed already:

root # emerge clamav

2. Add the service to the default runlevel:

root # rc-update add clamd default

The daemon will be launched automatically next time the computer boots.

3. The first download of the virus database has to be done manually:

root # freshclam

4. Start the daemon now:

root # rc-service clamd start

5. Create the Bash script ~/monitorDownloadsGUI with the following contents:

#!/bin/bash

DIR=$HOME/Downloads

# Get rid of old log file, if any
rm $HOME/virus-scan.log 2> /dev/null

IFS=$(echo -en "\n\b")

# Optionally, you can use shopt to avoid creating two processes due to the pipe
shopt -s lastpipe
inotifywait --quiet --monitor --event close_write,moved_to --recursive --format '%w%f' $DIR | while read FILE
# Added '--recursive' so that a directory copied into $DIR also triggers clamscan/clamdscan, although downloads
# from the Web would just be files, not directories.
do
# Have to check file length is nonzero otherwise commands may be repeated
if [ -s $FILE ]; then
# Replace 'date >' with 'date >>' if you want to keep log file entries for previous scans.
date > $HOME/virus-scan.log
clamdscan --fdpass --move=$HOME/virus-quarantine $FILE >> $HOME/virus-scan.log
kdialog --title "Virus scan of $FILE" --msgbox "$(cat $HOME/virus-scan.log)"
fi
done

Make it executable:

user $ chmod +x ~/monitorDownloadsGUI

6. Create the directory ~/virus-quarantine/ to store infected files pending investigation/deletion:

user $ mkdir ~/virus-quarantine

7. Install kdialog if it is not already installed:

root # emerge kdialog

8. Use ‘System Settings’ > ‘Startup and Shutdown’ > ‘Autostart’ to add the script ~/monitorDownloadsGUI to the list of script files that are automatically started each time you log in to KDE.

9. Log out then back in again, and you should see that everything is running as expected:

user $ rc-status | grep clam
 clamd                                                             [  started  ]

user $ ps -ef | grep clam | grep -v grep
clamav    1920     1  0 01:48 ?        00:00:00 /usr/sbin/clamd
clamav    1929     1  0 01:48 ?        00:00:00 /usr/bin/freshclam -d

user $ ps -ef | grep GUI | grep -v grep
fitzcarraldo      9143  8971  0 13:56 ?        00:00:00 /bin/bash /home/fitzcarraldo/.config/autostart-scripts/monitorDownloadsGUI.sh

10. To test, surf to http://www.eicar.org/ and download one of the EICAR test files into your ~/Downloads/ directory. You should see a pop-up KDialog window with a message similar to the following:

Virus scan of /home/fitzcarraldo/Downloads/eicarcom2.zip — KDialog

Mon 27 Feb 14:05:26 GMT 2017
/home/fitzcarraldo/Downloads/eicarcom2.zip: Eicar-Test-Signature FOUND
/home/fitzcarraldo/Downloads/eicarcom2.zip: moved to ‘/home/fitzcarraldo/virus-quarantine/eicarcom2.zip’

———– SCAN SUMMARY ———–
Infected files: 1
Time: 0.001 sec (0 m 0 s)

Note that the above-mentioned pop-up window may be preceded by one or more pop-up windows with an error message. I’m using the Chrome browser at the moment, but you may get a similar message if you are using another browser. Here is an example:

Virus scan of /home/fitzcarraldo/Downloads/.com.google.Chrome.Uh3oGm — KDialog ?

Mon 27 Feb 14:16:30 GMT 2017
/home/fitzcarraldo/Downloads/.com.google.Chrome.Uh3oGm: Access denied. ERROR

———– SCAN SUMMARY ———–
Infected files: 0
Total errors: 1
Time: 0.000 sec (0 m 0 s)

Read the error message and click ‘OK’, as this is not an actual problem; it is inotifywait detecting temporary files in the ~/Downloads/ directory during the download process. With larger files sometimes several such messages are displayed, presumably because the file being downloaded is being opened and closed more than once during the downloading process. This issue does not occur if you copy or move a file into ~/Downloads/ from another directory in your installation; try it and see for yourself. Then you only get the one pop-up window with the scan result for the file you put in ~/Downloads/.

Also have a look in ~/virus-quarantine/ and you will see the EICAR test file in that directory. You can delete it if you want (it is not infected with a real virus, so does no harm).

In future be sure to read the messages in the pop-up windows before clicking ‘OK’, as they will inform you that an infected file has been moved to the quarantine directory.

That’s all there is to it. Very simple, and quite handy if you want to check quickly that files you download don’t have a malware payload. Just make sure you download all files into ~/Downloads/ or they will not be checked automatically. Also, if you are given e.g. a USB pen drive with a file on it, you can copy the file to ~/Downloads/ if you want it to be scanned for malware.

How to capture a screenshot of the SDDM greeter screen

In my previous post I explained how to capture a screenshot of the LightDM greeter screen. The procedure is essentially the same for the SDDM greeter screen; only the Bash script differs slightly. The procedure is given below.

  1. If they are not already installed, install the packages x11-apps/xwd and media-gfx/imagemagick.

  2. Create the Bash script ~/sddm-greeter-capture.sh containing the following:
    TMPXAUTHORITY=$(ls /var/run/sddm/*)
    sleep 30
    DISPLAY=:0 XAUTHORITY=/var/run/sddm/$TMPXAUTHORITY xwd -root > /tmp/greeter.xwd
    convert /tmp/greeter.xwd /home/fitzcarraldo/greeter.png
    

    Make sure you make it executable:

    user $ chmod +x sddm-greeter-capture.sh

  3. Log out of the Desktop Environment so that the SDDM greeter screen is displayed.

  4. Press Ctrl+Alt+F2 to switch to VT2.

  5. Log in to you user account and enter the following command (do not wait for it to complete):

    user $ sudo /home/fitzcarraldo/sddm-greeter-capture.sh

  6. As soon as you have pressed Enter for the above command, press Ctrl+Alt+F7 to switch back to VT7.

  7. Wait for at least 30 seconds to be sure the Bash script has made a snapshot of the SDDM greeter screen, then log in.

  8. You should now find the file ~/greeter.png containing a snapshot of your SDDM greeter screen.

If you install media-libs/netpbm instead of (or as well as) media-gfx/imagemagick then you can use a different command to convert in the Bash script:

TMPXAUTHORITY=$(ls /var/run/sddm/*)
sleep 30
#DISPLAY=:0 XAUTHORITY=/var/run/sddm/$TMPXAUTHORITY xwd -root | xwdtopnm | pnmtopng > /home/fitzcarraldo/greeter.png

The resulting PNG image looks equally good to my eyes.

How to capture a screenshot of the LightDM greeter screen

  1. If they are not already installed, install the packages x11-apps/xwd and media-gfx/imagemagick.

  2. Create the Bash script ~/lightdm-greeter-capture.sh containing the following:
    #!/bin/bash
    sleep 30
    DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/$DISPLAY xwd -root > /tmp/greeter.xwd
    convert /tmp/greeter.xwd /home/fitzcarraldo/greeter.png
    

    Make sure you make it executable:

    user $ chmod +x lightdm-greeter-capture.sh

  3. Log out of the Desktop Environment so that the LightDM greeter screen is displayed.

  4. Press Ctrl+Alt+F2 to switch to VT2.

  5. Log in to you user account and enter the following command (do not wait for it to complete):

    user $ sudo /home/fitzcarraldo/lightdm-greeter-capture.sh

  6. As soon as you have pressed Enter for the above command, press Ctrl+Alt+F7 to switch back to VT7.

  7. Wait for at least 30 seconds to be sure the Bash script has made a snapshot of the LightDM greeter screen, then log in.

  8. You should now find the file ~/greeter.png containing a snapshot of your LightDM greeter screen.

If you install media-libs/netpbm instead of (or as well as) media-gfx/imagemagick then you can use a different command to convert in the Bash script:

#!/bin/bash
sleep 30
DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/$DISPLAY xwd -root | xwdtopnm | pnmtopng > /home/fitzcarraldo/greeter.png

The resulting PNG image looks equally good to my eyes.