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Archive for the ‘Power User’ Category

OpenSuSE Tumbleweed E20 on Raspberry Pi 3: accessing the enlightenment desktop over VNC after automatic logon

Posted by jpluimers on 2018/12/14

For a keyboard-less Raspberry Pi machine that functions as a read-only screen, I needed:

  • automatic logon
  • remote VNC accessibility
  • no screen blanking

I already had the E20 ([WayBackEnlightenment) X11 server running as that’s the first image on [WayBackHCL:Raspberry Pi3 – openSUSE that as a graphical UI that works.

Enable automatic logon (often called autologin)

Basically this is editing /etc/sysconfig/displaymanager and replacing the line

DISPLAYMANAGER_AUTOLOGIN=""

with one like

DISPLAYMANAGER_AUTOLOGIN="username"

After rebooting, the X11 session will automatically logon without asking for a password.

You can do this via yast too, in at least two ways:

Both posts are titled how to disable automatic logon, so apparently people do this the other way around but forgot how to restore.

Enabling VNC for the X11 session

This is done using x11vnc which exposes the X11 framebuffer over the VNC protocol (more background from the author at[WayBackx11vnc: a VNC server for real X displays).

Steps to get this working:

  1. sudo zypper install x11vnc
  2. sudo su username to the user that needs to logon
  3. As that user, save the X11 password using [WayBack] x11vnc -storepasswd (which is a VNC specific password you can choose yourself):

    x11vnc -storepasswd
    Enter VNC password:
    Verify password:
    Write password to /home/martijn/.vnc/passwd? [y]/n
    Password written to: /home/martijn/.vnc/passwd

  4. As the same user, create a shortcut that starts x11vnc with the stored password (unlike LXDE where the directory is `x11vnc.desktop, with E20 the directory is ./.local/share/applications):
    1. Run this command:

      cd ~/.local
      mkdir share
      cd share
      mkdir applications
      cd applications
      cat > x11vnc.desktop

    2. Paste this entry (omit the -shared option if you want only one VNC client at a time; see[WayBackxorg – How to setup multiple simultaneous access to x11vnc session – Ask Ubuntu and[WayBackSet up VNC so that multiple users can use VNC · Issue #1 · acrobotic/Ai_Demos_pcDuino):

      [Desktop Entry]
      Encoding=UTF-8
      Type=Application
      Name=X11VNC
      Comment=
      Exec=x11vnc -shared -forever -usepw -display :0 -ultrafilexfer
      StartupNotify=false
      Terminal=false
      Hidden=false

    3. Press Control-D (the End of Transmission character) to save the file.
    4. Run this command to make it automatically start (via [WayBackExecute Commands on startup Enlightenment / Applications & Desktop Environments / Arch Linux Forums):

      cd ~/.e
      mkdir e
      cd e
      mkdir applications
      cd applications
      mkdir startup
      cd startup
      echo >> .order "x11vnc.desktop"

  5. Enable port 5900 in the firewall.
  6. Reboot
  7. Wait for the system to come up
  8. Logon as user, then sudo -i to root
  9. Verify if there is VNC listening on port 5900:
    # ss -a -n | grep ":5900"
    tcp    LISTEN     0      32        *:5900                  *:*                  
    tcp    LISTEN     0      32       :::5900                 :::*                  
    # ps axjf | grep x11vnc
     1979  2048  2047  1944 pts/0     2047 S+       0   0:00                      \_ grep --color=auto x11vnc
     1811  1856  1856  1856 ?           -1 SNs   1001   0:00              \_ x11vnc -forever -usepw -display :0 -ultrafilexfer
    
  10. Verify from an external connection you can logon, for instance from a Mac terminal: open vnc://192.168.71.67:5900and logon using the VNC specific password you chose.

Disable screen blanking

Disable the screensaver using the xset (documented in[WayBackXSET(1) manual page):

xset -display :0 s off
xset -display :0 -dpms

You can verify display parameters on the primary display with the command xset -display :0 q.

Screen blanking settings:

> xset -display :0 q
Keyboard Control:
  auto repeat:  off    key click percent:  0    LED mask:  00000000
  XKB indicators:
    00: Caps Lock:   off    01: Num Lock:    off    02: Scroll Lock: off
    03: Compose:     off    04: Kana:        off    05: Sleep:       off
    06: Suspend:     off    07: Mute:        off    08: Misc:        off
    09: Mail:        off    10: Charging:    off    11: Shift Lock:  off
    12: Group 2:     off    13: Mouse Keys:  off
  auto repeat delay:  660    repeat rate:  25
  auto repeating keys:  00ffffffdffffbbf
                        fadfffefffedffff
                        9fffffffffffffff
                        fff7ffffffffffff
  bell percent:  50    bell pitch:  400    bell duration:  100
Pointer Control:
  acceleration:  2/1    threshold:  4
Screen Saver:
  prefer blanking:  yes    allow exposures:  yes
  timeout:  600    cycle:  0
Colors:
  default colormap:  0x20    BlackPixel:  0x0    WhitePixel:  0xffffff
Font Path:
  /usr/share/fonts/misc:unscaled,/usr/share/fonts/Type1/,/usr/share/fonts/100dpi:unscaled,/usr/share/fonts/75dpi:unscaled,/usr/share/fonts/ghostscript/,/usr/share/fonts/cyrillic:unscaled,/usr/share/fonts/truetype/,built-ins
DPMS (Energy Star):
  Standby: 605    Suspend: 606    Off: 607
  DPMS is Enabled
  Monitor is On
Font cache:
  Server does not have the FontCache Extension

No screen blanking differences in bold-italic:

> xset -display :0 q
Keyboard Control:
  auto repeat:  off    key click percent:  0    LED mask:  00000000
  XKB indicators:
    00: Caps Lock:   off    01: Num Lock:    off    02: Scroll Lock: off
    03: Compose:     off    04: Kana:        off    05: Sleep:       off
    06: Suspend:     off    07: Mute:        off    08: Misc:        off
    09: Mail:        off    10: Charging:    off    11: Shift Lock:  off
    12: Group 2:     off    13: Mouse Keys:  off
  auto repeat delay:  660    repeat rate:  25
  auto repeating keys:  00ffffffdffffbbf
                        fadfffefffedffff
                        9fffffffffffffff
                        fff7ffffffffffff
  bell percent:  50    bell pitch:  400    bell duration:  100
Pointer Control:
  acceleration:  2/1    threshold:  4
Screen Saver:
  prefer blanking:  yes    allow exposures:  yes
  timeout:  0    cycle:  0
Colors:
  default colormap:  0x20    BlackPixel:  0x0    WhitePixel:  0xffffff
Font Path:
  /usr/share/fonts/misc:unscaled,/usr/share/fonts/Type1/,/usr/share/fonts/100dpi:unscaled,/usr/share/fonts/75dpi:unscaled,/usr/share/fonts/ghostscript/,/usr/share/fonts/cyrillic:unscaled,/usr/share/fonts/truetype/,built-ins
DPMS (Energy Star):
  Standby: 605    Suspend: 606    Off: 607
  DPMS is Disabled
Font cache:
  Server does not have the FontCache Extension

Note that because DPMS is disabled, this entry is also gone:

Monitor is On

Limit the pager to 1 page

->

Based on:

–jeroen

Posted in *nix, *nix-tools, Power User, VNC, X11 | Leave a Comment »

macos – El Capitan /private/var/folders cache files consuming 30–40 GB – Ask Different

Posted by jpluimers on 2018/12/14

[WayBackmacos – El Capitan /private/var/folders cache files consuming 30–40 GB – Ask Different

TL;DR: a reboot will usually clean up most of the chaches and yes you can remove those caches by hand after closing the applications involved.

–jeroen

Posted in Apple, Mac OS X / OS X / MacOS, Power User | Leave a Comment »

The [WayBack] and [Archive.is] links in my blog and G+ stream

Posted by jpluimers on 2018/12/13

Answering a good question on [WayBack] Jeroen Wiert Pluimers – Google+:

Q:

Kevin Powick: Why do so many of your posts have [WayBack] embedded in the text? I’ve never been able to figure it out.

A:

On the blog they point to WayBack URLs of the link that succeeds it because I found out that web pages nowadays last a lot shorter than they used to be so link-rot has increased big time.

I still need to write a bookmarklet that automates that process for me: verify if a page is in WayBack, if not: try to store it, if it fails, store it in Archive.is, then generate the full HTML for me to put in the blog.

–jeroen

 

Posted in Blogging, Power User, SocialMedia, WayBack machine | Leave a Comment »

Links for Nagios openSuSE Tumbleweed monitoring (including Android devices)

Posted by jpluimers on 2018/12/13

For my link archive:

Non-stable repos:

–jeroen

Posted in *nix, Linux, Monitoring, Nagios, openSuSE, Power User, SuSE Linux, Tumbleweed | Leave a Comment »

on my research list: autossh

Posted by jpluimers on 2018/12/12

Having mainly used ssh as a means to connect to a shell on remote machines and occasionally a manual port forward.

I never noticed autossh where you can automate the ssh logon process to keep permanent port forwards up and running. Cool!

It’s on my research list now, as this will be useful probably sooner than later:

My initial impression is that autossh is a wrapper around the regular ssh client that allows reconnection upon communication failures.

–jeroen

Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, Power User, SSH, TCP | Leave a Comment »

 
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