ubuntu « My pensieve

Category: ubuntu

September 22, 2014

No more reinstall campaign #AvoidedReinstall

by viggy — Categories: FOSS, FSMK, linux, ubuntu — Tags: avoid, Avoidreinstall, campaign, FSMK, linux, reinstall, self, ubuntu — Leave a comment

How often do you screw your GNU/Linux based system such that you decide to reinstall your system? Are you the go-to person in your group for any issues with any GNU/Linux based OS? How often do you suggest to people who come to you that there is no other way to recover than re-installing?

I have been helping people to migrate to GNU/Linux based distribution, mainly Ubuntu. And its quite often that I come across people who while doing something or other have messed their system and need to help to fix it up. More than often, I used to give up quite quickly and ask them to take a backup using live-boot and reinstall the system. Many times, I would just search for first error I noticed and see if I could get solution online and if that didnt work give up and ask to reinstall. Though this is quick, it actually meant that I wasnt learning anything new. It also meant that many things in Ubuntu which might have been actual bugs might not be getting noticed due to this. And it also contradicted one of the popular examples I used to mention as to why Free Software is better than proprietary? Have you noticed the Blue Screen of Death, Can you fix it on Windows? Because Free Software allows you to study it and play with it, you can know why your system has actually crashed and try to understand how to fix it. Really? How often do we do that?

Hence I have decided to start this self-campaign and if possible motivate others to also follow it where in I put my maximum whenever I come across a messed up system to recover it without reinstall. The way the success of this campaign will be judged is by maximum number of systems I can avoid reinstall before coming across a system I am forced to reinstall as I cant find any other way around it. Hopefully as time goes on, the gap between every two systems forced to reinstall will increase which would mean I am improving/learning and avoiding many more systems from re-install.

I am already successful in doing it for 1 system. Hoorrrraaaayyyy!!!!! Hence #AvoidedReinstall 1 I spent 3 nights on it, close to 8-10 hours in all but finally it is recovered and system is now working without having to re-install Ubuntu. Hope to find sometime and blog about it also.

March 18, 2014

Configuring LDAP authentication for Ubuntu as client and Debian as server

by viggy — Categories: debian, FOSS, linux, tech, ubuntu — Tags: active, authentication, directory, LDAP, login, slapd — Leave a comment

Recently there was some request to see if a University can completely migrate to Ubuntu. One of their requirement was that their login for windows was getting managed by using Active Directory. I knew that LDAP is an alternative and hence I wanted to try this before I could commit anything to them.

I decided to make my home debian desktop system to be the server and my ubuntu laptop to be the client. following are the rough points that I needed to follow to get the LDAP authentication for Ubuntu working. There is already good enough documentation, but I still had to look for multiple sites and tits and bits of information from various sites helped me.

For Preparing the Server which was my debian system:

1) install slapd, migrationtools
2) run dpkg-reconfigure slapd and choose options
3) Then make changes in migrate_common.ph
4) Ou=People and ou=group is not added and hence have to be manually created and added.
5) Run migrate_passwd.pl and migrate_group.pl and add to ldap

Here mainly when I was referring Debian Wiki page, I was asked to use migrate_all_online.pl script which always used to fail for me for some or other reason. Having spent considerable time just to get past through that script, Thanks to this post, http://www.debuntu.org/how-to-set-up-a-ldap-server-and-its-clients/ , I realized that I actually didnt need to migrate all accounts to ldap and just had to use migrate_passwd.pl and migrate_group.pl.

One important thing to remember is that I had same username password for my users in my desktop and laptop, my server and client. If you dont have it, then you may have to create custom ldif files adding all data of users and then use ldapadd to add them to LDAP directory.

Use ldapsearch using:
ldapsearch -D “cn=admin,dc=viggy,dc=loc” -W -b “dc=viggy,dc=loc” “uid=root”
BaseDN is important to mention using -b switch

On the client side,

1) Install ldap-auth-client and nscd.

as per https://help.ubuntu.com/community/LDAPClientAuthentication

2) Add my_mkhomedir and my_groups in /usr/share/pam-configs and also make changes in /etc/security/group.conf

3) Finally also edit the /etc/nssswitch.conf to make it use ldap and then files/compat. If you want the system to rely only on LDAP, then remove the existing option and let only ldap be present.

It should look like this

passwd:         ldap compat
group:          ldap compat
shadow:         ldap compat

Now restart the nscd service, /etc/init.d/nscd restart

4) To check if the ldap authentication is working, just try to do sudo to a user and check in the /var/log/auth.log file if it mentions connecting to the ldap server.

ToDo:

1) I have not been able to understand how to add logging capability to slapd in the new cn=config configuration

2) Need to verify how to get all data from Active Directory and migrate to ldap.

February 9, 2013

GNU/Linux uptime worldwide

by viggy — Categories: FSMK, linux, tech, ubuntu — Tags: GLUG, GNU, linux, project, uptime — Leave a comment

Wont it be great to see what is the total time that users across the globe are spending on their GNU/Linux Desktops. What if every time a user signs in a system, their usage time is recorded and once in a while this usage data is uploaded in a server. We can then extract lots of data like how much time is being spent totally, which are most popular operating systems based used, based on average uptime, we can find out the type of users and their preferred operating systems.

For example, we can may be find that people who are using say 3-4 hours a day on GNU/Linux are mostly Ubuntu and people who are using say more than 12-14 hours a day are mostly on Debian or Mint giving an indication that new users choose Ubuntu but they slowly shift towards Debian or Mint. Again just a hypothetical example.

We can also plan to have a competition at GLUG level to see which GLUG is spending most of their time on GNU/Linux.

November 16, 2010

Split .avi video and .mp3 audio files in Ubuntu linux

by viggy — Categories: linux, tech, ubuntu — Tags: audio, ffmpeg, mp3, mp3splt, split, video — Leave a comment

I am presently thinking of bringing out a collection of music which I like very much. It wont include any voice but just music. For that I mainly had two issues, first to split video files that I had in .avi format and second to split audio files that I had in .mp3 format.

For video files, I used ffmpeg utility

ffmpeg -i input.avi -ss 00:01:10 -t 00:04:45 output_file.avi

where input.avi is the file from which you want to extract the music.
-ss is the start point of the music
-t is the duration from the start time till when the music is to be extracted
output_file.avi is the file in this the extracted music will be stored.

It will be in .avi format only. If required you can also convert it into audio files.
This gave me the exact chunk of the music video that I wanted for collection.

For Audio files, I used mp3splt utility. I used its gui, mp3splt-gtk which is very easy to use.
All I need to do was select the file from which I wanted to extract music. Select two splitpoints, one for the start and second for the end. And select split button given at the top of the gui. Its as simple as that. Since this utility was available in Ubuntu Repository, I didnt have issues even with installing it

September 30, 2010

Connect to Cisco VPN from Ubuntu 10.04

by viggy — Categories: ubuntu — Tags: cisco-vpn, IPSec, network-manager-vpnc, vpn — 1 Comment

Today I was trying to see if I can connect to office VPN from Ubuntu. Hence I tried to google and see if there is already
a solution for the same. I found that for Cisco VPN client, we need to install a package called network-manager-vpnc which is luckily available in Ubuntu repository. After that you need to create a file by any name, say remotevpn.conf in /etc/vpnc folder. In that just add the following contents in it.

Sec gateway
IPSec ID
Xauth username
Xauth password

Change the username as needed. After that just run the following command,

vpnc-connect remotevpn # here remotevpn should be replaced by the name
you had given to the conf file.

This will prompt you for a IPSec Secret password. Enter the Group password. Chances are that you might actually have a Encrypted password which you will have to convert into normal password. For that you can use the following site,

http://coreygilmore.com/projects/decrypt-cisco-vpn-password/

After entering the group password, it will prompt you for the password for the username you gave.
Enter the 4 digit password and the 6 digit RSA ID.

Thats it :). You are now connected to VPN network.

September 8, 2010

To enable Broadcomm wireless driver in Ubuntu 9.10

by viggy — Categories: schoolos, ubuntu — Tags: broadcomm, fwcutter, wireless — 1 Comment

I was trying SchoolOS on my laptop which is a derivative of Ubuntu 9.10. However my first problem with it was that my wireless driver was not working. I had known from my previous experience that I would have to probably install b43-fwcutter to get it working. However when I tried to install it, I found out that it was already installed. I still removed the package and installed again but still it did not help. So I googled for any help. I found a forum post where in I was suggested to try the packages given in http://www.broadcom.com/support/802.11/linux_sta.php . I downloaded the 32 bit package and followed the Readme.txt given along with the package. Within 2 minutes my network driver detected the wireless device and I was able to surf using my wireless connection.

August 6, 2010

How to checkout from cvs

by viggy — Categories: linux, ubuntu — Tags: checkout, command, cvs, login — Leave a comment

how to checkout from cvs from command line.

First set the CVSROOT environment variable. In our case, let the CVSROOT be

CVSROOT = :pserver:vignesh.prabhu@cvs:/opt/cvs/reps/mmp3000

Now login to the cvs server using the following command:

$cvs login

This will prompt you for your account password. After you have successfully authenticated with password, you can checkout from the cvs server using the following command:

cvs co -r tag10 project/sub_project

where tag10 is the tag from which you want to checkout

and project/sub_project is the part of the project which you want to start checkout.

If you directly want to checkout from HEAD, then use the following command:

cvs co project/sub_project

June 24, 2010

GPG key error while doing apt-get update

by viggy — Categories: ubuntu — Tags: apt-get, aptitude, gpg, ubuntu — 2 Comments

I had entered a new repository path in my sources.list file and hence I did

sudo apt-get update

However I got the following error:

W: GPG error: http://hudson.gotdns.com binary/ Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 9B7D32F2D50582E6
W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 10975893E549B1AC

When I looked for a solution on internet, I found the following solution to add the gpg key in my system.

NOTE: This can only be done by a root user, hence in Ubuntu, u will have to do sudo su before executing these commands.

root@vignesh-laptop:gpg --keyserver pgpkeys.mit.edu --recv-key 9B7D32F2D50582E6 gpg: requesting key E549B1AC from hkp server pgpkeys.mit.edu gpg: key E549B1AC: public key "Launchpad yorba" imported gpg: Total number processed: 1 gpg: imported: 1 (RSA: 1)

This will request key from the server mentioned in –keyserver and display whose public key it is.

After this execute the following command. This will store the the gpg key in your system as a trusted gpg.

root@vignesh-laptop:/home/vignesh# gpg --armor --export 10975893E549B1AC | apt-key add - OK

Now do
sudo apt-get update
to successfully update from the newly added repositories.

June 17, 2010

recording feature of vim

by viggy — Categories: linux, tech, ubuntu — Tags: record, vim — 2 Comments

Good article on recording feature of vim can be found in the link given below.

http://www.thegeekstuff.com/2009/01/vi-and-vim-macro-tutorial-how-to-record-and-play/

May 21, 2010

how to configure proxy for apt-get?

by viggy — Categories: linux, tech, ubuntu — Tags: apt, apt-get, aptitude, conf, http, proxy — Leave a comment

To configure proxy settings for apt-get or aptitude or synaptic manager, all you have to do is edit the file, /etc/apt/apt.conf .

Here you have to mention the following 3 lines::

vignesh@vignesh-laptop:~$ cat /etc/apt/apt.conf
Acquire::http::proxy “http://username:password@host:port”;
Acquire::ftp::proxy “ftp://username:password@host:port”;
Acquire::https::proxy “https://username:password@host:port”;

Once you have made the above changes in /etc/apt/apt.conf , you will be able to use apt-get, aptitude or your synaptic manager through the proxy.

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