Monday, June 24, 2013

Ubuntu : Upgrade Git


Sometimes simply updating from "Ubuntu update" won't update/upgrade some of the required packages. We need to to it manually by adding necessary repositories. To upgrade git:
sudo add-apt-repository ppa:voronov84/andreyv
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install git
If the first command result in error "couldn't connect to host"

Ubuntu : Java alternatives

java alternative

Ubuntu will include openJDK by default. If you install some other version or Sun JDK, then the first installation is set to be the default one.

To check if there are any other java installations:

update-java-alternatives -l
Change the default to any of them:
update-java-alternatives -s NAME-OF-IT

Ubuntu : Install Sun java 6

java 6

Ubuntu has dropped including Sun/Oracle Java in its repository, and added OpenJDK. But, the former is more reliable than latter, and is also must for some applications.
Here is a way to add Sun java 6:
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java6-installer
Possible error : "couldn't connect to host"

To make this version as default: here.

If you want to install java 7, instead of last command try
sudo apt-get install oracle-java7-installer
If you are under proxy network or seen a error like
Cannot add PPA: 'ppa:webupd8team/java'.
Please check that the PPA name or format is correct.
and if you are sure that the PPA is working, the try
sudo -E add-apt-repository ppa:webupd8team/java
and proceed with remaining commands.

Ubuntu : Error "couldn't connect to host"

This error will be resulted mostly because of the user permissions. To go through it, we need the simulate the initial login mode:
sudo -i
Now run the commands which resulted in the above error, but without prefixing with 'sudo'. Remember to go out of this mode after running your commands. To go out:

Ubuntu : Adding a new repository (PPA)


To add a repository ppa:
sudo add-apt-repository ppa:user/ppa-name
sudo apt-get update
Sometimes adding a repository may result in error related to missing key. Then copy that key and run following command

sudo apt-key adv --recv-keys --keyserver KEY
Do this for each of the missing keys.
Now re-run the above two commands.

If you are under proxy network or seen a error like
Cannot add PPA: 'ppa:user/ppa-name'.
Please check that the PPA name or format is correct.
and if you are sure that the PPA is working, the try
sudo -E add-apt-repository ppa:user/ppa-name

Ubuntu: Set Network proxy system-wide including Terminal


Set the proxy in "Network Proxy" setings and click "apply system-wide", and also at the following locations. Some terminal applications need them.

sudo gedit /etc/apt/apt.conf.d/95proxies
Acquire::http::proxy "http://username:passwd@proxy:port/";
Acquire::ftp::proxy "ftp://username:passwd@proxy:port/";
Acquire::https::proxy "https://username:passwd@proxy:port/";
sudo gedit .bashrc
export http_proxy=http://username:passwd@proxy:port
export https_proxy=http://username:passwd@proxy:port
export HTTP_PROXY=http://username:passwd@proxy:port
export HTTPS_PROXY=http://username:passwd@proxy:port

Requires both CAPITALS and small ones. Some applications accepts only CAPITALS.

Wednesday, June 19, 2013

Openlogic : Open Source Software Database


Here is a open source software repository, which contains almost every version of the packages. This will be useful for all those who need any older version of the package, which sometimes is difficult to find. So, I'm sharing the link here:
Type the package name in search field and select the version you need.

Tuesday, June 18, 2013

Ubuntu : Mount a volume with ROOT privileges


My system is having multiple internal hard disks and due to some memory concerns I have to work on the second drive(hdd2). Then on visiting "/mnt/hdd2", I found entire drive  is protected by root. To change the privileges, I tried the normal way:
sudo chmod 755 /mnt/hdd2
Result : NO CHANGE.
Then tried
sudo chmod a+x /mnt/hdd2
Result : NO CHANGE.
No I googled I find:
sudo chmod -R 755 /mnt/hdd2
Result : To my surprise NO CHANGE
Here is the solution:
sudo chown -R chaithanya:chaithanya /mnt/hdd2
Result : SUCCESS ('chaithanya' is the username).

Monday, June 17, 2013

Setting up / Working with Android Source code


1. Install Ubuntu 10.04, as the Android root is built on it.

2. Update the system - Run Update manager and install new packages

3. Update the system settings:
4. Install sun java 6
5. Installing required packages:
sudo apt-get install git-core gnupg flex bison gperf build-essential \zip curl zlib1g-dev libc6-dev lib32ncurses5-dev ia32-libs \x11proto-core-dev libx11-dev lib32readline5-dev lib32z-dev \libgl1-mesa-dev g++-multilib mingw32 tofrodos python-markdown \libxml2-utils xsltproc
6. Upgrade git
7. Installing Repo:
mkdir ~/bin
curl > ~/bin/repo
chmod a+x ~/bin/repo
8. Initialising a Repo client:
repo init -u -b android-4.0.1_r1
If any error saying "HTTP request failed", open file "~/bin/repo" and change "https" in the beginning to "http".
If the error "GnuTLS recv error (-9): A TLS packet with unexpected length was received" occurs, try http instead of https above. i.e.,
repo init -u -b android-4.0.1_r1

9. Download Android Source
repo sync
10. Add Git tags:
$ gpg --import
Copy and paste the following code and press Ctrl-D:

Version: GnuPG v1.4.2.2 (GNU/Linux)

11. Setup ccache:
export USE_CCACHE=1
export CCACHE_DIR=<path-to-your-cache-directory>
prebuilts/misc/linux-x86/ccache/ccache -M 50G
12. Initialize the build:
$ . build/
13. Choose the target:
$ lunch full-eng
14. Build the code: (-j4 : 4 threads. Change the value as per your system configuration)
$ make -j4
15. Run:
$ emulator

Tuesday, June 4, 2013

Clean-up GRUB entries

Whenever a kernel update is installed, your system adds an entry into GRUB. And while booting you can see a very long list, depending on how many updates you have installed. Here is a simple way to clean the GRUB.
  • Open Synaptics package manager.
  • Remove "linux-image-2.6.xxxx" and "linux-headers-2.6.xxxx" corresponding to old kernel images.
  • Update the grub using: "update-grub"

If you wish to set a background image for your GRUB, then goto "/etc/grub.d/" and open the theme file(debian_theme) and set "use_bg=false" to "true". Change the WALLPAPER, to point to the desired image(Better use .png file).

To apply the changes to the grub: "update-grub"

Monday, June 3, 2013

SVN Error: "OPTIONS of 'https://…' could not connect to server (…)"


Today when I tried to download source-code of an application from a repository on googlecode, an error saying "could not connect to server" occurred. I thought the repository might have been down and not available for download. Then I tried the same URL in web browser and it worked.
On searching for a while, I found that this problem is created by proxy settings. SVN needs the proxy settings, apart from that you applied system-wide settings. Then I came to know a solution which worked perfectly. Here it is:
svn --config-option servers:global:http-proxy-host=MY_PROXY_HOST --config-option servers:global:http-proxy-port=MY_PROXY_PORT checkout
If the proxy server needs authentication, then try this:
svn --config-option servers:global:http-proxy-host=MY_PROXY_HOST --config-option servers:global:http-proxy-port=MY_PROXY_PORT --config-option servers:global:http-proxy-username=USERNAME --config-option servers:global:http-proxy-password=PASSWORD checkout
For various available options: