Setting up VNC for GDM Login

Nov 12, 2009
Tested on: Ubuntu 9.10 (Karmic Koala)

Ubuntu has a Remote Desktop server (Vino), which can be easily configured. But personally I found it to be too slow (even on 100Mbps connection) and there is no option to get it up & running before actual GDM login. One of the faster alternatives is x11vnc. It allows one to view remotely and interact with real X displays with any VNC viewer. Following are the steps to enable x11vnc immediately after GDM (or XDM, KDM etc) loads. We will be effectively using XDMCP over VNC.
  1. Enable XDMCP
    • Older Ubuntu version: System->Administration->Login Screen Setup-> Tab XDMCP->Enable XDMCP. You can disable "Honor Indirect Requests".
    • Karmic Koala: There is no XDMCP Tab in settings. So add "Enable=true" in [xdmcp] section of /etc/gdm/custom.conf (or gdm.conf for older version of GDM). Check here for detailed instructions.
    • For others, just look through the settings and find XDMCP, make sure it's enabled.
  2. Disable Desktop Sharing with Vino under System -> Preferences -> Remote Desktop. Install x11vnc from repository.
  3. Create password for VNCsudo x11vnc -storepasswd yourpasswordhere /etc/x11vnc.pass
  4. Configure GDM to run x11vnc when it loads:sudo nano /etc/gdm/Init/Default & add this line to the file just before exit 0:/usr/bin/x11vnc -nap -bg -many -repeat -clear_keys -rfbauth /etc/x11vnc.pass -rfbport 5900
  5. Edit gdm configuration to make sure that x11vnc is not killed after being started.sudo nano /etc/gdm/custom.conf Add / edit KillInitClients option in the [daemon] section to:KillInitClients=false Also check this FAQ for recent changes and other workarounds in x11vnc regarding KillInitClients.
  6. Restart gdm (you can just reboot), and you are good to go.
Few things to be noted:
  1. x11vnc does NOT have any options for locking the server machine's display on connection with client. If this is an important security issue then other vnc servers like vino, tightvnc etc should be used. Refer comments for more details.
  2. You may experience endless key repetition / key pressing when logged from a client. Use "-repeat" options with x11vnc to check this behavior. Check this discussion for other alternatives.
  3. I experience initial delay (about 6-7 secs) in response from x11vnc whenever I try to make a new connection. Though, it responds nicely after initial glitch.
Edits:
17 Jan, 2010: [debug] changed to [daemon], as it makes more sense according to GDM manuals.
18 Jan, 2010: Added FAQ link in step 5.

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Code Block for Blogger / Blogspot

Nov 12, 2009
Added following to template (Layout->Edit html) in body section: code { font-family: Courier; margin:.75em 0; border:1px dashed #CCC; padding:5px 15px; display: block; background-color: #F4F5F7; overflow: auto; white-space: pre; } Above box itself is result of <code>...</code> tag.

An example:code block retains the whitespace & any other formatting in plain text.
Another Example:T h i s is a realllllllllllllllllyyyyyyyy looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooonnnnnnnnnnnnnnnngggggggggggggggg cooooooooooooooooooooode block
This is output of<blockquote> ... </blockquote>
blockquotes does NOT retains the whitespace OR any other formatting in plain text.

Note: Any HTML code between <code></code> is also treated as HTML. Use this HTML encoder to encode to HTML code before posting. Or, paste the HTML code in Compose tab (not in "Edit HTML" tab) of the post editor (Make sure that you have selected "Show HTML literally" in Compose Settings under Post Options).
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Install style files in LyX

Sep 19, 2009

LyX is a frontend to LaTeX and so installation of any style file in LyX essentially mean: (1) installation of that style file in underlying LaTeX; and then (2) getting that style file work in LyX (using LyX layout files). Installation method for different types of style files are given below:

Install LaTeX class (.cls)
  1. create new directory with name <your-class-name> under /usr/share/texmf-texlive/tex/latex/
  2. copy <your-class-name>.cls file (& other files, if present) in the new directory
  3. sudo texhash
  4. create  a file <your-class-name>.layout in ~/.lyx/layouts
  5. edit the layout file according to the instructions given in Chapter 5 of "Customizing LyX: Features for the Advanced User" (Help->Customization in LyX).
  6. open LyX and click 'tools -> Reconfigure' and restart LyX when done. The new Document Class should be available now.
For Example, to install IEEEconf class file, download the zip files from here. Create .cls file by executing 'latex IEEEconf.ins'. Copy the folder IEEEconf to /usr/share/texmf-texlive/tex/latex/. Run sudo texhash. Find IEEEtran.layout file & copy it to a new file named IEEEconf.layout in ~/.lyx/layouts (IEEEconf and IEEEtran are very similar, so IEEEtran-layout file can be used as layout file for IEEEconf). Edit the the second line in IEEEconf.layout from
# \DeclareLaTeXClass{article (IEEEtran)}
to
# \DeclareLaTeXClass{article (IEEEconf)}
and it should turn up when you reconfigure LyX.
Install LaTeX style (.sty)

Style file (.sty) is an addition to class files (.cls) files and they provides special formatting rules which overrides the similar rules in class  files, if present. So each style file must be associated with a class file. Installation process is similar to that of class files (see previous section of this post). Layout files (step 5 above) have different format. Instructions are given in Chapter 5 of "Customizing LyX: Features for the Advanced User" (Help->Customization in LyX).

For Example, to install ACRA style file, download the files from here. Copy the file acra.sty to /usr/share/texmf-texlive/tex/latex/ACRA/. Run sudo texhash. Find article.layout file & copy it to a new file named acra.layout in ~/.lyx/layouts (acra.sty uses "article" class). Edit the the second line in acra.layout from
#  \DeclareLaTeXClass{article}
to
#  \DeclareLaTeXClass[article, acra.sty]{article (ACRA)}
Then add in next line

Preamble
    \usepackage{acra}
EndPreamble

and it should turn up when you reconfigure LyX.

Install BibTeX Style (.bst)
  1. create new directory with name <your-bib-style-name> under /usr/share/texmf-texlive/bibtex/bst/
  2. copy <your-bib-style-name>.bst file (& other files, if present) in the new directory
  3. sudo texhash
  4. open LyX and click 'tools -> Reconfigure' and restart LyX when done.
  5. open LyX and click 'tools -> TeX Information' and choose BibTex Styles. Click 'Rescan' The new BibTeX should be available now.

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Useful applications in Ubuntu

Sep 16, 2009

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