Ubuntu General

• When ssh connection is slow

  /etc/nsswitch.conf

                  #hosts:          files mdns4_minimal [NOTFOUND=return] dns nis mdns4
                  hosts:          files mdns4_minimal [NOTFOUND=return] dns nis

  /etc/ssh/ssh_config

                  #    GSSAPIAuthentication yes
                  #    GSSAPIDelegateCredentials no

• When putting the NIS client on Ubuntu, it sometimes fails to start up the NIS client before the network is up at boot time

  • Workaround 1

    In /etc/init/ypbind.conf, add

                        pre-start script
                        …
                        sleep 10
                        end script

    to the last line of the pre-start script to delay startup by 10 seconds. If this still fails occasionally, simply Ctrl+Alt+F2 to get to the console screen and log in, then

                        sudo service ypbind restart

    to restart the NIS client and Ctrl+Alt+F7.

  • Workaround 2

    For personal use, you can give up the NIS client and create an account with the same user name and user ID.

• Combine pdf files

  Normally, you can user pdftk to combine pdf files, but windows pdfpdfpdf (pdfc.exe) will bookmark the file name.

• Writing software for pdf files

  In Linux, the only software that can write to pdf files is okular. If you want to write more things, it would be better to use pdf xchange viewer via wine. However, installing directly from wine seems to cause various problems (in my case, it always crashed when saving files). Therefore, I used PlayOnLinux and installed it for 32bit. Japanese inline input is not possible, but you can use a separate editor and copy-paste the input itself.

• png viewer with easy redisplay

  Okular and qpdfview can be done with F5.The former is very sophisticated, the latter is light. eog (Eye of GNOME : an image viewer) is a bug or something, so it doesn't work well.

• Install vncviewer

                  sudo apt-get install vncviewer

  The point is that if you install from Ubuntu Software Center, you get something weird.

• Black screen in vlc media player

  Tools→Settings→Video→Output→X11 video output
  The same method can be userd to solve this problem with SMPPlayer and others.

• Create boot USB stick

  Gparted is useful for formatting USB sticks. UNetbootin is useful to create a boot USB stick from an iso file. Incidentally, iso files for network installation of Ubuntu can be obtained from here.

• Fast Fourier Transform on Ubuntu

  For a little Fourier transform.Install

                  apt install libfftw3-3 libfftw3-dev libfftw3-doc

  Compile

                  gcc hoge.c -lm -lfftw3

• Clearing the Cache

                  sudo sysctl -w vm.drop_caches=3

Lubuntu in general

• Abiword, Gnumeric

  If you see these two software names, you should delete them immediately. If you open and save doc, xls, etc. sent from office, etc. with these software, the characters will be garbled and you will never be able to recover them.

• Accessing Windows network (samba) with lubuntu

                  smb://domain;user@server/folder

• Users with UID less than 1000 are not displayed on the login screen, even though /etc/lightdm/users.conf has minimum-uid=500.

  There is a UID_MIN in /etc/login.defs, so set this from 1000 to 500
  This method did not work in Linux Mint. I don't know what the solution is. At this point, using Linux Mint is no longer an option for me personally.

• Dual monitors in lubuntu

  menu→settings→monitor settings→turn on both monitors→ check monitor names in xrandr and

                  xrandr --output Monitor2 --right-of Monitor1

  If presenting in office, it is safe to use the same resolution
  If the desired resolution is no available, do

                  xrandr --addmode VGA1 1280x1024
                  xrandr --output VGA1 --mode 1280x1024

  Also, when presenting with libreoffice impress, it often happens that the projector is not recognized by libreoffice impress slideshow→slideshow settings→multiple displays, even though the main and sub displays are switched rather frequently.

                  xrandr --output Monitor2 --right-of Monitor1
                  xrandr --output Monitor2 --left-of Monitor1
                  xrandr --output Monitor2 --above Monitor1
                  xrandr --output Monitor2 --below Monitor1
                  xrandr --output Monitor2 --same-as Monitor1

  and fight (I couldn't do my best at the previous conference...) The fundamental solution, it is to install both ubuntu and lubuntuThe fundamental solution is to install both ubuntu and lubuntu, and start up ubuntu only when you give a presentation.

• Dual monitors by default

  Even if you set dual monitors by xrandr, it will be restored if you log off, so always set dual monitors.Create a file named $HOME/.config/autostart/multidisplay.desktop, and put

                  [Desktop Entry]
                  Name=multidisplay
                  Exec=xrandr (configuration)
                  Type=Application

• Dual monitor and touchscreen

  xinput to find out the id of the touchscreen. xrandr to find out the name of the monitor. Then

                  xinput --map-to-output id monitor

• Install both Ubuntu and Lubuntu

  If only using Lubuntu, specifying Lubuntu desktop during installation. However, if you use both, the installation will fail, or even if it succeeds, various problems will occur and you will be in trouble later. Therefore, it is better to install Lubuntu on Ubuntu later.

                  apt-get install lubuntu-desktop

  The right side of the login screen will ask whether you want to use Ubuntu or Lubuntu.

• Specify the program to start first in lubuntu

  If there is a corresponding .desktop file in /usr/share/applications, just copy it to $HOME/.config/autostat. If it is a command, write the command to $HOME/.config/lxsession/Lubuntu/autostart.

• Digital clock settings

                  %x %a %T

  Display is extravagant

Ubuntu20.04LTS

• Window tiling shortcut using Super keys in lxqt is gone

  Setting it in .config/openbox/lxqt-rc.xml does not work. It seems to be due to a conflict with the lqxt keyboard shotcut called lxqt-globalkeys.Moreover, lxqt-globalkeys does not allow window tiling. What are you thinking?
  The solution is to use the window tiling shortcut using the Super key, Ctrl+Super seems to be recognized as Super, so I'll live with that. Incidentally, I added the following description between and in lxqt-rc.xml.

                  <!-- Keybindings for window tiling -->
                  <keybind key="C-W-Up">
                    <action name="Maximize"/>
                  </keybind>
                  <keybind key="W-Left">        # HalfLeftScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>0</x><y>0</y><height>97%</height><width>50%</width></action>
                  </keybind>
                  <keybind key="W-Right">        # HalfRightScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>-0</x><y>0</y><height>97%</height><width>50%</width></action>
                  </keybind>
                  <keybind key="W-Up">        # HalfUpperScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>0</x><y>0</y><width>100%</width><height>50%</height></action>
                  </keybind>
                  <keybind key="W-Down">        # HalfLowerScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>0</x><y>-0</y><width>100%</width><height>50%</height></action>
                  </keybind>
                

  After this

                  openbox --reconfigure

  Cinnamon has a shortcut similar to this by default, but Cinnamon is heavy and has many problems...

• Japanese input conversion with half/full size keys

  This is the same as before.It is safe to do.

                  sudo apt install fcitx-mozc

• Make Jupyter-notebook's default browser Chrome

  It launches in Chrome on Ubuntu and Cinnamon, but Firefox on Lubuntu.

                  $HOME/anaconda3/bin/jupyter-notebook --generate-config

  Then edit $HOME/.jupyter/jupyter_notebook_config.py

                  # c.NotebookApp.browser = ''

  to

                  c.NotebookApp.brower = '/usr/bin/google-chrome'

• Make Coogle chrome the default web browser in LXQT (also solves the above problem)

  FireFox starts up even though I set it up with Chrome.
  Settings→LXQt settings→LXQt Configuration Center→LXQt session settings→Prescribed applications→Web browser→/usr/bin/google-chrome
  Why can't I set it from the chrome side?

• Install zoom

  Download and install from a miserable software manager like Discover or something like that, because you'll get something miserable

                  sudo apt install zoom_amd64.deb

• Install Hengshan font

  Install from CUI, as you can't find it in Discover or other miserable software manager. I feel like it gets more and more?

                  sudo apt install fonts-aoyagi-kouzan-t
                  sudo apt install fonts-kouzan-mouhitsu

• Making WPS Office Japanese

  It is not enough to move the ja_JP folder to the mui folder.
  First, download ja_JP.7z from here and extract it.Move it to $HOME/.local/share/Kingsoft/office6/mui/. If there is no mui folder, create one. Then edit $HOME/.config/Kingsoft/Office.conf

                  [General]
                  PersistentStatus=0
                  languages=ja_JP

  Add the red part and restart WPS Office.

• SpaceFM icon is crappy (small)

  Settings→LXQt settings→Appearance→Change icon theme

• Alsa volume control not found in lxqt.

                  alsamixer

• Wired LAN not recognized during OS installation

  I219-V controller is not recognized until Ubuntu20.04.2. Therefore, you need to install Ubuntu 20.04.3 (or later). That means Japanese Remix (20.04.1) is no good.

• Application indicator icons are wrong

  I have confirmed that fcitx-mozc, Skype, Slack, discord, and to a lesser extent sylpheed are also wrong. I have looked around, but it doesn't work, and some people seem to have stopped using lxqt because of this. So I would like to stop using lxqt and lubuntu here too. Thank you very much. → I will use lxde. Since then lxde related.

• The behavior of slack in lxde is strange

  Specifically, when I try to open xdg from chrome, it doesn't return to the slack app, but opens a new chrome instead. So I'm going to register it.

                  echo "x-scheme-handler/slack=slack.desktop;" >> ~/.local/share/applications/mimeinfo.cache
                  cp $HOME/.config/autostart/slack.desktop $HOME/.local/share/applications/

• I want to do detailed power management

  lxde does not have an app for power management, so I'll borrow xfce4 power management

                  sudo apt install xfce4-power-manager

  Then, in /etc/xdg/lxsession/LXDE/autostart, add

                  @xfce4-power-manager

  lxqt-powermanagement might be ok, but let's not touch lxqt anymore for a while.

• Ctl + Alt + T does not bring up terminal

  In $HOME/.config/openbox/lxde-rc.xml, between <keyboard> and </keyboard>

                  <!-- Keybindings for window tiling -->
                  <keybind key="C-W-Up">
                    <action name="Maximize"/>
                  </keybind>
                  <keybind key="W-Left">        # HalfLeftScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>0</x><y>0</y><height>100%</height><width>50%</width></action>
                  </keybind>
                  <keybind key="W-Right">        # HalfRightScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>-0</x><y>0</y><height>100%</height><width>50%</width></action>
                  </keybind>
                  <keybind key="W-Up">        # HalfUpperScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>0</x><y>0</y><width>100%</width><height>50%</height></action>
                  </keybind>
                  <keybind key="W-Down">        # HalfLowerScreen
                    <action name="UnmaximizeFull"/>
                    <action name="MoveResizeTo"><x>0</x><y>-0</y><width>100%</width><height>50%</height></action>
                  </keybind>
                
                  <!-- Launch a terminal on Ctrl + Alt + T-->
                  <keybind key="C-A-T">
                    <action name="Execute">
                      <command>qterminal</command>
                    </action>
                  </keybind>

  In addition, I included the above keyboard tiling. After this

                  openbox --reconfigure

  I tried qterminal this time, but I think anything is fine.

• Install obs-studio and the plugin backgroundremoval.

  backgroundremoval is distributed on git, but the installation instructions there do not allow you to install it (you will be asked for a file that may not exist in the world, such as obs-frontend-apiConfig.cmake). Instead, use pacstall to install.
  First of all, preparation. pacstall is installed.

                  git clone https://github.com/pacstall/pacstall.git
                  cd pacstall
                  sudo ./install.sh

  Uninstall obs-studio once and install the latest version again (in some cases you may need to re-install more).

                  sudo apt remove obs-studio --auto-remove
                  sudo add-apt-repository ppa:obsproject/obs-studio -r
                  sudo apt update
                  sudo apt install obs-studio

  install what you need

                  sudo apt install -y libobs-dev libopencv-dev language-pack-en build-essential cmake

  Install backgroundremoval

                  pacstall -I obs-backgroundremoval-git

  Sometimes it fails to install because it failed to install onnxruntime. The probable cause is listed in the backgroundremoval installation instructions.

                  wget https://github.com/microsoft/onnxruntime/releases/download/v1.7.0/onnxruntime-linux-x64-1.7.0.tgz
                  sudo tar xzvf onnxruntime-linux-x64-1.7.0.tgz --strip-components=1 -C /usr/local/ --wildcards "*/include/*" "*/lib*/"

  This is probably due to running. In this case, the files

                  /usr/local/include/cpu_provider_factory.h
                  /usr/local/include/cuda_provider_factory.h
                  /usr/local/include/onnxruntime_c_api.h
                  /usr/local/include/onnxruntime_cxx_api.h
                  /usr/local/include/onnxruntime_cxx_inline.h
                  /usr/local/include/onnxruntime_session_options_config_keys.h
                  /usr/local/lib/libonnxruntime.so.1.7.0
                  /usr/local/lib/libonnxruntime.so

  should be removed. If that doesn't work, extract onnxruntime directly under the download folder.

                  wget https://github.com/microsoft/onnxruntime/releases/download/v1.7.0/onnxruntime-linux-x64-1.7.0.tgz
                  tar zxvf onnxruntime-linux-x64-1.7.0.tgz

  According to the author of obs-backgroundremovel-git, this should complete the installation, launch obs-studio and backgroundremoval should be added to the video filter. If this does not work, exit obs-studio, install v4l2loopback, etc. first, and then launch obs-studio again. If this does not work, re-install obs-studio.

                  sudo apt remove obs-studio --auto-remove
                  sudo apt install obs-studio

• Building a virtual camera with obs-studio

  Here (Jpn) was helpful. To be frank, you should look here.
  Installing v4l2loopback

                  sudo apt install v4l2loopback-dkms v4l2loopback-utils

  Installing obs-v4l2sink
  From here, download installer and

                  sudo apt install ./obs-v4l2sink.deb
                  cd /usr/lib/x86_64-linux-gnu/obs-plugins
                  sudo ln -s /usr/lib/obs-plugins/v4l2sink.so

  Load V4l2loopback (This needs to be done every reboot)

                  sudo modprobe v4l2loopback devices=1 video_nr=10 card_label="OBS Cam" exclusive_caps=1

  Now OBS Cam appears as a camera option for zoom and skype.Start obs-studio, select Tools → v4l2sink → Device Path as /dev/video10 → click Start to activate the virtual camera, and you will be able to view the screen created in obs-studio on zoom and skype during this time. This works fine for zoom and discord, but for skype, it seems that the basic resolution and the camera resolution need to be matched in order to work properly. Go to "Settings", specify the resolution, and restart obs-studio.