November 25, 2009

Download Manager Gwget For Ubuntu

Downloading large files might consume much of your precious time, which is why most people prefer using some download manager. I never felt the need to install one myself, but it just occurred to me that I should try one, because I might need it one day for downloading some large files.

Check out the list of various download managers available at http://www.ubuntugeek.com/list-of-download-managers-available-in-ubuntu.html.

I installed Gwget, which offers a GNOME front-end to the Wget application.

Installation

Open the terminal, and type,

varsha@varsha-laptop:~$ sudo aptitude install gwget

Usage

1. Select Gwget Download Manager from Applications-> Internet.

2. Click New. Copy-paste the URL of the file you want to download and browse the directory where you want to save it.

3. Click OK.



November 21, 2009

Rectifying apt-get GPG Error

The following apt-get error is quite common while updating.

....

W: GPG error: http://ppa.launchpad.net karmic Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 991E6CF92D9A3C5B
....


Generally, we just try searching for a public key and and adding the key to the apt key-list, which sometimes doesn't work.

There is a better option. Try any one of the following links.

1. http://keyserver.ubuntu.com/

2. http://minsky.surfnet.nl/

3. http://keyserver.fabbione.net/

All you have to do is:

1. Copy-paste the key from the error on the terminal to the search-box, preceded by 0x.

2. Click Submit Query.

3. Click on the link next to pub.

4. Add the key to the key-list by typing in the terminal,

varsha@varsha-laptop:~$ wget -q "http://keyserver.ubuntu.com:11371/pks/lookup?op=get&search=0x991E6CF92D9A3C5B" -O- | sudo apt-key add -

Note that the server address may vary. So, make changes accordingly in your command.

An OK in the next line tells you that the key has been successfully fetched from the key-server.

You can repeat the above steps if you get the error for more than one key.

[Source:
http://www.rebelzero.com/fixes/apt-get-gpg-error-public-key-not-available/88]



November 13, 2009

Backing Up home Directory

A few days back, I suddenly started facing many problems, all at the same time. Many of my software started misbehaving, and eth0 (ethernet) failed to connect (two instances). Later, on booting, an error showed up saying that /home couldn't be found. Thankfully, I had another account. Using that account, I did the following.

1. Open the terminal, and type,

oracle@varsha-laptop:~$ su

Enter the root password, when prompted.

2. Go to your home directory, and list all the files and directories.

root@varsha-laptop:/usr/lib/oracle/xe# cd /home
root@varsha-laptop:/home# ls
lost+found samba varsha varsha1


3. See if directories of your home directory are accessible using cd.

root@varsha-laptop:/home# cd varsha
root@varsha-laptop:/home/varsha# ls

4. Estimate file size.

root@varsha-laptop:/home/varsha# du -sh /home/varsha
12G /home/varsha


5. Copy home directory to another disk having free space.

root@varsha-laptop:/home/varsha# cp -R /home/varsha /media/disk-1

You can now install Linux, and copy the important documents to the home directory.



Giving sudo Privileges To A User

The /etc/sudoers.tmp file must be edited, in order to give sudo access to any user.

1. Open a terminal and type,

varsha@varsha-laptop:~$ EDITOR=gedit sudo visudo

visudo is used for editing the sudoers file. See the manual for more details.

varsha@varsha-laptop:~$ man visudo

2. At the end of the file, append,

system_username ALL=(ALL) ALL

where system_username is the username of the user whom you want to give a sudo privilege.

Graphically, it can be done as given in this tutorial.



Reinstalling GRUB

GRUB is generally lost due to Windows install or if your MBR gets erased. Follow the simple steps given below to restore GRUB.

1. Boot your computer using a Linux live CD.

2. Open a terminal and type,

liveuser@liveuser-laptop:~$ sudo grub

This gives you the grub prompt.

3. To inform the GRUB about the location of the GRUB files, we should know it ourselves first. Generally, it is (hd0,1), which means hda (primary controller master) in the second partition.

If you know where they are, type ,

grub> root (hd0,1)

Else to find out, type,

grub> find /boot/grub/stage1

4. Then install it on hd0 (or any other hard drive in your case), which is the MBR of the first HDD.

grub>setup (hd0)

5. To quit, type

grub> quit

6. Reboot your machine.

liveuser@liveuser-laptop:~$ reboot

The GRUB menu appears on system reboot.



New RSS Feed For Twitter

I have taken up a project (in fact my first ever project) under Shreyank Gupta (of Red Hat) as my mentor for making an RSS feed for Twitter.

The following are the plans for the software.

1. It will be made using Ruby on Rails (RoR).

2. It will accept RSS feeds of Twitter in an xml file.

3. It will have a database for storing the tweets, and additional features can be added later.

4. Any tweet can be clicked to get a conversation if available.

5. I plan to complete the software in 2 months, starting from 28th December 2009. The first fifteen days will be utilized for learning RoR.

6. A testing model will be ready within the third week of February. After any required changes, the final working model will be ready by the last week.

I hope I will be able to complete the software as per the above-laid plans.



November 11, 2009

Installing Flash Player on Ubuntu 9.10

Flash player, useful for watching videos online, can be downloaded and installed as follows, on Ubuntu Karmic.

1. Download the plugin from here.

2. Save the file. I saved it in my 'Setup_Files' directory.

3. Open the terminal, and cd to the directory where you have saved your file.

varsha@varsha-laptop:~$ cd /home/varsha/Setup_Files

4. Uncompress the file.

varsha@varsha-laptop:~/Setup_Files$ sudo tar -xzf install_flash_player_10_linux.tar.gz

5. Copy the extracted file to the 'Mozilla plugins' directory.

varsha@varsha-laptop:~/Setup_Files$ sudo cp libflashplayer.so /usr/lib/mozilla/plugins/

6. Delete the tar.gz and the extracted file, if you want to, using the rm command.

varsha@varsha-laptop:~/Setup_Files$ rm libflashplayer.so