Setting up VNC for GDM Login

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

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

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

• Wallpaper-tray: Automatic wallpaper changing utility
  
• Graphical Disk Map: Hard-disk space visualizer
• MusicBrainz Picard: MusicBrainz music tagger, Cross-platform
• CheckGmail: Alternative Gmail Notifier for Linux
• Dropbox: Online sync, backup and sharing utility, Cross-platform
• HandBrake: Video converter (for iPods)
• UbuntuTweak: GUI based configuration tool, for beginners
• Mendeley Desktop: Desktop and online research management tool. Integrates with CiteULike, Cross-platform 
• SMPlayer: Complete front-end for MPlayer, Cross-platform
  

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Disable Autorun & Autoplay in Xp

Prevents the spread of autorun.inf viruses from flash drives (or any kind of removable drives.

• Autoplay: Download disable_autoplay.reg and double click to run. Accept yes to all dialog boxes. Restart your computer.
• Autorun: Download disable_autorun.reg and double click to run. Accept yes to all dialog boxes. Restart your computer.

[ Reference(s): Link1, Link2, Link3, Link4 ]

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Emacs Cheat Sheet

C-x is same as Ctrl-x
M-x is same as Alt-x
<#> represents a numeric value

FILE
Open	C-x C-f
Save	C-x C-s
Save As	C-x C-w
Save All	C-x s
Close Buffer	C-x k
Quit	C-x C-c
EDIT
Undo	C-_
Begin Selection	C-space
Cancel Selection	C-g
Cut Selection	C-w
Cut Line (text on right side of the cursor)	C-k
Paste / Yank	C-y
Copy Selection to Numbered Clipboard	C-x r s <#>
Paste from Numbered Clipboard	C-x r i <#>
Forward Delete	Delete    C-d
Forward Delete Word	M-d
Backward Delete	Backspace
Backward Delete Word	C-Backspace    M-Backspace    M-Delete
Complete word (based on words in open buffers)	M-/
Rectangle Edits
Copy rectangle	C-x r r
Cut / kill rectangle	C-x r k
Paste / Yank rectangle	C-x r y
Create blank rectangle	C-x r o
SEARCH
Search / Move to next search hit	C-s
Search / Move to previous search hit	C-r
Regexp Search / Move to next hit	M-C-s
Regexp Search / Move to previous hit	M-C-r
Search and Replace	M-% then y for each replacement                     ! to replace all
Goto Line Number	M-x goto-line <#>    M-g g <#>
Move to previous matching bracket	M-C-b
Move to next matching bracket	M-C-f
WINDOW
Move to & fro in buffers	C-x right-arrow-key    C-x left-arrow-key
Choose Window	C-x, C-b
Move to top of page	C-Home-key
Move to bottom of page	C-End-key
Move to beginning of current line	C-a    Home-key
Move to end of current line	C-e    End-key
Maximize / Display only one buffer	C-x 1
Split Horizontal	C-x 2
Split Vertical	C-x 3
Switch Focus Between Windows	C-x o
Activate Menu Bar	M-`
FORMATTING
Indent Selection	M-C-\
Convert to uppercase (till end of current word)	M-u
Convert to lowercase (till end of current word)	M-l
Capitalize Word    (Convert 1st letter of word to uppercase)	M-c
Uppercase Selection	C-x, C-u
Lowercase Selection	C-x, C-l

Other useful cheat sheets:

• Keyboard shorcut reference - Highly recommended
  
• Emacs keyboard shortcuts

Emacs configuration files:

• The very unofficial .emacs home
• .emacs file by Alex 
• Example 1
• Example 2
• My .emacs file (copy the contents to ~/.emacs)

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Change default Home, Desktop and documents path in Ubuntu

• Edit ~/.config/user-dirs.dirs and set your desired path.

[ Reference(s): Ubuntuforums ]
 

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ProFTPD Virtual User Setup with AuthUserFile

1. Edit or add following to proftpd.conf
   
   AuthOrder mod_auth_file.c
   AuthUserFile /etc/proftpd/ftpd.passwd
   AuthGroupFile /etc/proftpd/ftpd.group
   RequireValidShell off
2. Get uid and gid
   
   cat /etc/passwd | grep <username>
   cat /etc/group | grep <groupname>
3. Add users to ftpd.passwd
   
   ftpasswd --uid <uid> --gid <gid> --gecos "Full Name" --name <username> --shell /bin/false --home <path> --passwd
4. Add Groups to ftpd.group
   
   ftpasswd --gid <gid> --name <groupname> --group
   
5. Add members to a group
   
   ftpasswd --gid <gid> --name <groupname> --member <membername> --group
6. Set permissions on the ftpd.passwd and ftpd.group files
   
   chmod 400 /etc/proftpd/ftpd.passwd /etc/proftpd/ftpd.group
   chown proftpd.nogroup /etc/proftpd/ftpd.passwd /etc/proftpd/ftpd.group
7. Restart ProFTPD
   
   /etc/init.d/proftpd restart

[ Reference(s): Link1, Link2 ]

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Disable ipv6 in Ubuntu

1. sudo gedit /etc/modprobe.d/aliases
2. Find the line: alias net-pf-10 ipv6
3. Edit this to: alias net-pf-10 off
4. Save the file and reboot
5. Check ipv6. There should not be any output to any of the following commands.
   ip a | grep inet6
   lsmod | grep v6
6. change network.dns.disableIPv6 to true in about:config of Firefox.
   

[ Reference(s): Ubuntuforums ]
 

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Picasa 3 behind proxy in Ubuntu

1. cd to /opt/picasa/bin/ OR /opt/google/picasa/3.0/bin
2. then execute: ./wrapper regedit
3. navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
   edit or create binary/dword value ProxyEnable with value 1.
4. edit or create string value ProxyServer with value proxy:port
   For example, if 144.16.192.245 is your proxy address and 8080 is port then set ProxyServer value as 144.16.192.245:8080
   

[ Reference(s): Picasa faq ]

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Canon PIXMA iP1700 driver on Ubuntu

(or use windoze on virtualbox non-OSE edition with usb support)

1. Add following lines to sources.list
   deb http://mambo.kuhp.kyoto-u.ac.jp/~takushi/ubuntu ./
   deb-src http://mambo.kuhp.kyoto-u.ac.jp/~takushi/ubuntu ./
2. Install packages: libcnbj-2.6 bjfilter-2.6 pstocanonbj
3. Use Canon iP2200 drivers in CUPS settings.

[ Reference(s): Link1, Link2, Link3 ]
 

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Firefox - Addons

Use "Siphon" to sync addons across different computers.

• Adblock Plus
• AutoCopy
• Auto Context -  user popup menu on text selection
• AutoHideStatusbar
• Bar Tab
• Better Gmail
• Better Youtube
• Clear Cache button / Clear Private Data
• Context Search - adds option to select search engine on right-click context menu
• Define Word / Define
• DownloadHelper
• Download Statusbar
• Fission
• Flashblock
• FlashGot
• Gmark
• Google Gears
• Google Toolbar
• Greasemonkey
• Keyconfig
• Menu Editor
• Mouse Gestures Redox / All-in-one Gestures
• Multiproxy Switch
• Omnibar - adds capability similar to Google Chrome's location bar
• Persona for firefox - Lightweight theme manager from Mozilla (in-built since Firefox 3.6)
• Split Browser
• Tab Mix Plus
• URL Suffix - Continued
• Voyage - History management
• Weave / Firefox Sync

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Hyperlinks on mouseover tooltips - Firefox

(Similar to Opera)

• install Greasemonkey addon
• install Link Tooltip script, mirror link (rename to .js)

Note: This script conflicts with WYSIWUG editors (like google sites, blogspot editor) and adds a title (url of the link) to the links, each time the editor is loaded. Add these sites in the list "excluded sites" of the script from Greasemonkey preferences to avoid this.

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Enable incompatible firefox-addons

(Due to firefox version check)

• add new boolean key extensions.checkUpdateSecurity and set it to false in about:config page.
• Starting from Firefox 3.6 new preference is used. Check MozillaZine page for details. Here are the steps for different versions:
  
  • Firefox 3.6 & later: add new boolean key extensions.checkCompatibility.<firefox-version> and set it to false in about:config page. (For example, for firefox 3.6 the key should be extensions.checkCompatibility.3.6)
  • Prior to firefox 3.6: add new boolean key extensions.checkCompatibility and set it to false in about:config page.

To add new boolean key, right click on about:config page -> New -> Boolean.

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About Fluky-Logs

Disclaimer: The information in this web-log is often purely experimental and serve as a guideline to me. I am NOT responsible for any damage caused to any system on following these guidelines. You can follow these instructions at your own risk.

I respect intellectual property rights and copyrights. I usually put a set of references in each post (hyperlinked or otherwise) stating the source of information, if any. In case these information violates any rights, please inform me. I will take required action.

You can find more about me on my Google+ profile and can contact me by using the contact form below (or else follow this link).

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