Sunday, 28 April 2013

What is dconf editor, how is it useful ?

Dconf is
  • low-level configuration system whose main purpose is to provide a backend to GSettings on GNOME 3.X desktops.
  • dconf is a simple key-based configuration system. Keys exist in an unstructured database.
  • dconf system can be considered as a kind of replacement for gconf system which was used in GNOME 2.X series desktop.
  • dconf-editor is a Graphical Editor for Simple key-based configuration system which is dconf.
Install dconf Editor
Launch dconf Editor
  • To launch dconf Editor open command launcher (Alt+F2) and run command "dconf-editor".
    Alt + F2 ==> dconf-editor
  • Alternatively you can press left "Win" key or (Alt+F1) to open "Activities" and type "dconf" upon which you can see dconf Editor appearing grouped under "Applications".
dconf Editor Essentials
Find keys
 The various keys can be found by invoking search settings from top panel and then plugging in appropriate "search string" as shown below
dconf-editor Find Keys
 dconf Editor is a very useful configuration editing tool and the inner "workings" are as follows:-
  • All the settings are categorised broadly under Schemas.
  • All the Keys that logically belong together are grouped together under Schemas.
  • The various key's values can be changed by double clicking on them and entering new values. To save new settings we need to press return key .
  • To restore original values we can always use the "Set to default" button at the bottom of the tool.
dconf Editor Usage
The tool can be used for many purposes like:-
  • Changing preferences/settings for many native GNOME applications settings. Example:- Get Totem working again after crash by changing schema "org.gnome.totem"
  • Perform some advanced settings which is sometimes not possible to do from even the applications. It is possible to reduce inbox refresh time to 30 seconds in Evolution. In this case it is accomplished by changing schema "org.gnome.evolution.mail"
    Evolution interface allows minimum refresh rate of 1 minute
    Evolution set inbox refresh rate
    dconf Editor allows reduction of refresh rate to 30 seconds.
    dconf-editor Evolution set inbox 30 sec refresh rate
  • Change default directory where the screenshots are stored if "Print Screen" button is pressed. In this case schema that is modified is "org.gnome.gnome-screenshot"
    Print Screen default Save Folder
  • We can change mouse button modifier (Modifier to use for modified window click actions) from <SUPER> or "Win" key to <ALT>. You can use "Alt" key and click on any open window to "drag" it around. The schema to be changed in this case is "org.gnome.desktop.wm.preferences".
    dconf-editor mouse button modifier <Alt>
  • It can serve as a replacement / alternative for "gnome-tweak-tool" and "gnome-control-center". Most of the settings in Tweak tool are available / changed using dconf Editor.
  • Change mouse from left to right click by editing the schema "org.gnome.settings-daemon.peripherals.mouse" as shown below.
    dconf-editor left handed mouse button settings

Saturday, 13 April 2013

Why should we install mozplugger on openSUSE 12.3, GNOME 3.6 ?

 MozPlugger is a generic Mozilla plug-in that allows the use of standard Linux programs as plug-ins for media types on the Internet. MozPlugger will help the Mozilla / Gecko based browsers to handle a variety of file formats like pdf, office formats (xls, xlsx, ppt, pptx, doc, docx), LibreOffice file formats etc. Without installing mozplugger we find that very few file types are present in "Helper Applications" window in both SeaMonkey and Firefox.
SeaMonkey with few content types in Helper Applications
SeaMonkey Before Mozplugger Installation
Firefox also shows only a few content types in Application preferences
Firefox Before Mozplugger Installation
When i try to open a sample xls file hosted online SeaMonkey tries to download and open it outside the browser.
SeaMonkey open with xls before mozplugger installation
Download and Install Mozplugger
Step 1:- First step would be to Configure Community Repositories in YaST 
Step 2 :- Before we proceed to download the rpms we need to understand what type of rpms we need. 32 bit Vs 64 bit OS architecture in Linux
Step 3 :- Since i use a 64bit OS I downloaded the following rpms
  • mozplugger-1.14.3-3.fc18.x86_64.rpm from link
  • mozilla-filesystem-1.9-8.fc18.x86_64.rpm from link
Step 4 :- I dumped these rpms into a directory and Converted the directory into a repository using YaST
Step 5 :- I open terminal (Alt+F2 ==> gnome-terminal) and install mozplugger using command "sudo zypper in mozplugger"
Post installation lot of content types are present in Helper Applications window
SeaMonkey Helper Applications After Mozplugger Installation
Post installation, I can open same xls "inside" SeaMonkey . LibreOffice opens the file in embedded mode inside the browser.
SeaMonkey LibreOffice opesn xls in embedded mode after mozplugger installation

Converting a Plain RPM Directory into a repository using YaST

 The following are the steps involved in converting a "Plain RPM Directory" into a repository using GTK-YaST on openSUSE 12.3, GNOME 3.6 :-
  • Dump all the rpm files you have in a suitable directory under your "Home" directory. I have all my rpms in directory "~/Software/rpms"
  • Press Left "win" key / Alt+F1 to bring up Activities window / launcher.
  • Then type "install" and it will bring up an application called "Install/Remove Software". Click on that to open YaST Software Manager.
  • Click on menu Configuration==>Repositories to navigate to "Repositories" window
  • Click on the add button in this window and it will take you to "MediaType" window where you need to choose "Local Directory" and press on "Next" button.
  • In the next window provide appropriate "Repository Name" and "Path to Directory" where your rpms are present. Also choose the option "Plain RPM Directory." and press on "Next" to complete the process.
  • You will now find  the "rpms" repository in the main window of YaST software Manager.
Screencast showing creating local repository using YaST
Note:- The trick for converting Nautilus Pathbar to textual input entry is to press Ctrl+L

Image resize and rotate using Nautilus on openSUSE 12.3, GNOME 3.6

 The Nautilus-Image-Converter is an extension that allows you to resize / rotate images from Nautilus. This extension is very useful when uploading images to websites (size limitations), creating thumbnails etc.
Installation & Usage
Step 1:- We need to Configure Community Repositories in YaST, GNOME 3.6, openSUSE 12.3
Step 2:- Launch command launcher(Alt+F2) and open terminal using command "gnome-terminal".
Step3:- Using zypper we can install the relevant extension using command "sudo -u root zypper in nautilus-image-converter".
 Step4:- Use the context menu (or) right click menu to "rotate" and resize images. The extension automatically appends a ".resized" and ".rotated" string to the names of newly created files, lest the original file gets overwritten.
Screenshot showing Nautilus "resize". Resize supports "resize to pixels", "scaling" and "custom size" functions.
Nautilus Resize
Screenshot showing Nautilus "rotate". Rotate supports "pre-defined rotations" and "custom angle" functions.
Nautilus Rotate

Graphical frontend for Systemd on openSUSE 12.3, GNOME 3.6

For the UN-initiated :-
  • systemd, init - systemd system and service manager
  • systemctl - Control the systemd system and service manager
Sample usage of systemd :- Restart Network Service using Systemd
 If you are not comfortable with running systemctl / systemd commands from console / terminal then you can install "systemd-ui" which acts like a Graphical front-end for systemd system and acts like a service manager.
Install and Use systemd-ui
Step 1:- We need to Configure Community Repositories in YaST, GNOME 3.6, openSUSE 12.3
Step 2:- Launch command launcher(Alt+F2) and open terminal using command "gnome-terminal".
Step3:- Now, it is possible to install systemd-ui using the command "sudo -u root zypper in systemd-ui".
Zypper Install Systemd-ui
Step 4:- Launch the systemd-ui using the command "gnomesu systemadm"
Step5:- Using this tool you can
  • Check Current status of the Service,
  • View Service dependencies,
  • Start Service,
  • Stop Service,
  • Restart Service,
  • In-activate Service etc..
Systemd System Manager

Thursday, 4 April 2013

Download Favourite pictures from Flickr on openSUSE 12.3, GNOME 3.6

 To download pictures that you have marked favourite from the popular Photo sharing site Flickr you can use an application called "FlickrFaves". It is a Java based application which means that  you need to have openJDK or Sun/Oracle JRE installed on your system.
Getting Started
Downloading and Installing FlickrFaves:-
 There is no need to install anything except that you need to setup up Java/JRE on you system. All you need to do is download the jar which is marked / labelled as "executable "and "launch the jar" to use it.
Use FlickrFaves
 Open a quick command launcher (Alt+F2) and open the terminal using command "gnome-terminal".
Step 2:-
Launch jar using the following command from terminal
java -jar /home/<ProfileName>/Downloads/FlickrFaves-2.0.4.jar
 On pressing "Authorize" button it will open the default web browser and take you to a page where you need to "Login" and "Authorize" the application to enable FlickrFaves to use Flickr.
After successful Authorisation you will see a success page
Step 4:-
 Comeback to FlickrFaves application and click on "Complete Authorization".
Step 5:-
 Configure your download folder and other settings like "number of files to download" and start downloading your stuff.
After downloading your pictures it will show a download successful message like this
Add FlickrFaves to GNOME Activities
Step 1:-
 Open command launcher(Alt+F2) and use the command "alacarte" to open GNOME 3.X menu editor
Step 2:-
 Add the relevant command(java -jar <Path>FlickrFaves-2.0.4.jar) and create a menu item as show below
You can now locate FlickrFaves in Activities


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