Ubuntu Tweaks

April 27, 2020

Ubuntu Tweaks

BtrFS maintenance

balance tree:

btrfs balance start -dusage=50 -dlimit=2 -musage=50 -mlimit=4 /

weekly scrub:

btrfs scrub start -B -d -c 2 -n 4 /

BtrFS snapshot settings

https://wiki.archlinux.org/index.php/snapper

snapperd is managing the snapshots
there are a couple of systemd services to trigger snapshots

Disable snapshot on boot:

systemctl disable snapper-boot.service
#systemctl enable snapper-boot.service # to undo that

Edit /etc/snapper/configs/root to reduce snapshot pressure on the system:

Comparison of pre/post

# start comparing pre- and post-snapshot in background after creating
# post-snapshot
BACKGROUND_COMPARISON="no"

This can be computationally very annoying on big filesystems if set to yes

Timeline based snapshots can be deactivated

# create hourly snapshots
TIMELINE_CREATE="no"

Of course you would have to perform these manually if wanted

# create a snapshot that will be cleaned up by the timeline algo according to the retention settings
snapper -c root create -c timeline

Check updatedb settings

/etc/updatedb.conf

This should not include .svn folders, .git folders or btrfs snapshots

You can even completely remove the package if you do not make use of its features

apt remove mlocate

Midnight Commander - Color scheme

Add this to the ~/.config/mc/ini file:

[Colors]
base_color=lightgray,default:\
normal=lightgray,default:\
selected=black,green:\
marked=yellow,default:\
markselect=white,green:\
errors=white,red:\
menu=lightgray,default:\
reverse=black,lightgray:\
dnormal=white,default:\
dfocus=black,green:\
dhotnormal=brightgreen,default:\
dhotfocus=brightgreen,green:\
viewunderline=brightred,default:\
menuhot=yellow,default:\
menusel=white,black:\
menuhotsel=yellow,black:\
helpnormal=black,lightgray:\
helpitalic=red,lightgray:\
helpbold=blue,lightgray:\
helplink=black,cyan:\
helpslink=yellow,default:\
gauge=white,black:\
input=black,green:\
directory=white,default:\
executable=brightgreen,default:\
link=brightcyan,default:\
stalelink=brightred,default:\
device=brightmagenta,default:\
core=red,default:\
special=black,default:\
editnormal=lightgray,default:\
editbold=yellow,default:\
editmarked=black,cyan:\
errdhotnormal=yellow,red:\
errdhotfocus=yellow,lightgray

Do not put newlines between the color definitions! Write them as a single line! I only did it for readability.

[Colors]
base_color=lightgray,default:normal=lightgray,default:selected=black,green:marked=yellow,default:markselect=white,green:errors=white,red:menu=lightgray,default:reverse=black,lightgray:dnormal=white,default:dfocus=black,green:dhotnormal=brightgreen,default:dhotfocus=brightgreen,green:viewunderline=brightred,default:menuhot=yellow,default:menusel=white,black:menuhotsel=yellow,black:helpnormal=black,lightgray:helpitalic=red,lightgray:helpbold=blue,lightgray:helplink=black,cyan:helpslink=yellow,default:gauge=white,black:input=black,green:directory=white,default:executable=brightgreen,default:link=brightcyan,default:stalelink=brightred,default:device=brightmagenta,default:core=red,default:special=black,default:editnormal=lightgray,default:editbold=yellow,default:editmarked=black,cyan:errdhotnormal=yellow,red:errdhotfocus=yellow,lightgray

Hide user from login screen

Reconfigure AccountsService. To hide a user named XXX, create a file named

/var/lib/AccountsService/users/XXX

containing two lines:

[User]
SystemAccount=true

If the file already exists, make sure you append the SystemAccount=true line to the [User] section.

Edit Gtk style

To add border to windows in Ubuntu 18.04:

gedit ~/.config/gtk-3.0/gtk.css

Then add the following:

  decoration {
    border: 2px solid #333333;
    background: gray;
  }

After saving the file, remember refresh gnome using this command:

    setsid gnome-shell --replace

To customize the active title bar background colors. (use :backdrop for inactive windows)

  .titlebar {
    background: #404040;
  }

  .titlebar:backdrop  {
    background: #000000;
    color:white;
  }

CPU stalls on boot

INFO: rcu_sched self-detected stall on CPU

The culprit was, a setting in BIOS, AMD C1E Support was set to Enabled and setting it to Auto or Disabled fixed the issue for me! No more stalls/hangs!

Disable IP v6

Edit /etc/sysctl.conf or create a new file inside /etc/sysctl.d, for example /etc/sysctl.d/10-ipv6-disable.conf

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

Run

sysctl -p

to refresh with the new configuration.

Disable floppy drive

Removes the kernel driver for floppy drive detection

echo "blacklist floppy" | sudo tee /etc/modprobe.d/blacklist-floppy.conf
sudo rmmod floppy
sudo update-initramfs -u

Preview JPEG and videos over USB

Smartphones are sometimes mounted as MTP (default for Sony XPERIA) and not Mass Storage. This impacts on preview.

Switch the phone into USB Mass Storage mode

Oracle Java

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer

Firefox activate pipelining

about:config

network.http.pipelining -> true
network.http.pipelining.maxrequests -> 32
network.http.pipelining.ssl -> true
network.http.proxy.pipelining -> true

http://www.techfragments.com/481/the-12-best-firefox-aboutconfig-performance-tweaks/

Reduce swappiness

https://wiki.ubuntuusers.de/Swap#Swapnutzung-einstellen

Ubuntu defaults to 60.

sudo sysctl vm.swappiness=25

Find process from window

xprop _NET_WM_PID | sed 's/_NET_WM_PID(CARDINAL) = //' | ps `cat`

This will make your cursor a cross with which you can click on an open window. It will report the PID and command in the terminal you ran it in.

In general, xprop and xwininfo will provide you with a lot of information about an open window.

Preload

Not always recommended, might misbehave. I turned it off

sudo apt-get install preload

https://launchpad.net/ubuntu/wily/+package/preload

Annoying Legitimate polkit

I attacked the /usr/share/polkit-1/actions/org.freedesktop.accounts.policy file and tried different values for <action id="org.freedesktop.accounts.change-own-user-data">;

I set these values as shown:

<defaults>
  <allow_any>yes</allow_any>
  <allow_inactive>yes</allow_inactive>
  <allow_active>yes</allow_active>
</defaults>

Kill all polkit processes

sudo killall polkit-gnome-authentication-agent-1

Nautilus: Disable CTRL+Scroll

https://wiki.ubuntu.com/Keybindings

Nothing built in even dconf-editor seems to provide control about the mouse behavior

apt-get install xbindkeys
xbindkeys --defaults > $HOME/.xbindkeysrc

Find key combinations:

xbindkeys -k

File: ~/.xbindkeysrc

# disable ctrl + scroll wheel by binding it to /bin/true
"/bin/true"
  Control + b:5 + release

"/bin/true"
  Control + b:4 + release

killall xbindkeys && xbindkeys

((Source1: http://raymondmoul.com/disable-ctrl-scroll-zooming-ubuntu/)) ((Source2: http://blog.hanschen.org/2009/10/13/mouse-shortcuts-with-xbindkeys/))

xbindkeys works somewhat but not reliably.

Finally I think the only way is to modify nautilus's source code:

src/nautilus-view.c

in function:

nautilus_view_handle_scroll_event

In order to download the source and re-build it, do this:

Install all build-dependencies for nautilus: sudo apt-get build-dep nautilus
Run apt-get source nautilus in a directory you want the source.
cd into the nautilus- directory.
Run debuild -us -uc -i -I. This creates an unsigned source, unsigned changes file and one or more binary packages. You'll find these one level of a folder lower.
dch -i or debchange -i
debcommit or dpkg-source --commit
Install the package(s) using sudo dpkg -i /path/to/binary-package1.deb /path/to/binary-package2.deb [...].
Make changes to the source, and rebuild/install as many times as you like.

You can apply this recipe to any Debian/Ubuntu package.

https://help.ubuntu.com/community/UpdatingADeb

Setting up environment

http://packaging.ubuntu.com/html/fixing-a-bug.html

sudo apt-get install packaging-dev

CD Rip Morituri

https://blog.mdosch.de/2015/03/25/empfehlung-cd-ripper-morituri/

Thunar thumbnails

To restore proper thumbnail generation:

pkill tumblerd