Good bye wordpress.com

Hi, I’m moving to a new home today – ershadk.com. Please update your email subscriptions and feed settings. Thank you very much for reading and sharing your opinions on little posts I wrote and please do that in my new blog too. And I would like to thank wordpress.com for hosting my little blog for last few years. All posts and comments in this blog are copied to the new blog. That’s it, Welcome to ershadk.com!

Tathva memories @ NITC

“.. I’m leaving this campus today. I will miss the late-night hangouts with Kartik and Pankaj.. I will miss the stay in Kartik’s room with Arjun and Rohit (If you are reading this, All the best for your IAS, brother). I will miss Ramnath, Arnab and all my  friends here and this great institution.. I’m sure I will be back here for the next event.. With a million beautiful memories in 4 days.. Adieu NITC..”

Anagram Solver in C

Hi, Here’s a small anagram solver written in C. It works based on generating permutations of given string and comparing them using a dictionary. For fast search in dictionary, the program first creates an index of the starting location of each alphabet. It takes a few minutes to process long words.

Here’s the source code. Suggestions are always welcome, Greetings

Update: There’s a little problem in using the term ‘anagram solver’ here. An anagram solver finds words from another valid word – But this program finds words from the characters of given valid/invalid word.  Thanks to technikhil for the info

Why I started loving Archlinux

We like simplicity. We like everything new.

It’s been some years since I switched completely to GNU/Linux. I always wondered at its stability, security, features, community and at the people who use it. GNU/Linux helped me to have exciting computing experience all the time filled with wonders and fun. I forgot about the existence of Antivirus software. Forgot the time I feared autorun.inf and weird executable files. Forgot BSOD and EULA. Now, everything is open. Met many new people, similar interests bonded us. People who use GNU/Linux have always been very helpful. They share knowledge instead of pirated software. They teach us to fish. A kind of special relationship rooted between us, in a world connected by computer networks and its underlying complex abstractions. At this moment, I would like to thank everyone who made lives of people like me colourful.

I had been using Debian Squeeze for a while and was happy with that. Had its complete repo offline which helped me to install any package in spite of the very slow internet connection I had then. Though the things went smooth, I faced some issues during that time with the compilation of new software from source. Fixing dependency issues were pain. The new source of package requires new version of dependencies which were not available in repo. Compiling them from source always created new pains. Updating software/repo was not possible because of the slow speed of internet. Taking laptop to college and updating from there also didn’t work due to various technical and non-technical reasons. I felt like I was completely forbidden from trying new versions of software. I was in a kind of lock then. Suddenly, one fine day, I got a broadband internet connection!

I don’t have words to express how much happiness I felt. Now the scenario has completely changed. I can now change the Debian repo to testing or sid, try new packages, configure backports or update what ever I want. But, I thought it was time for a change. Changes are the spices of life, indeed.

I wanted to install another distro from the mainstream. First, I thought of Fedora 15 which is a very good OS and hacks by Rajeeshettan in it always inspired me. Also I had used Fedora 14 for several months. But in Fedora too, I missed an element of simplicity and playfulness. The point with these type of operating system is that it comes with all basic packages preconfigured and giving us less opportunities to play with those.

Next choice was obviously Archlinux. I have been hearing about it since I met my another GNU/Linux guru – Ashikettan. He blogs about Arch much and talks about it often. Also, I had tried it once months before when I had speedy internet connection. The best thing about Archlinx is that it is a rolling distro, and new packages are always readily available!

To install, I got the 64bit iso image from Arch website and made thumb bootable with abock. The installation went smooth and had a nice time configuring various things along with my favourite desktop environment – KDE. I was not really able to use KDE since the version in Debian Squeeze was a bit buggy and it crashed often. I was using Gnome 2.x then. Now, I’m really happy with KDE 4.7.0 with a distro which can be updated easily using its sweet package manager – pacman. Arch also has a wonderful knowledge base – The ArchWiki. ArchWiki has many tutorials to play with for beginners and for expert users.

To talk about packages in Archlinux, I don’t have words! I remember trying to install new version of Ipython in debian which comes with a new tool called qtconsole. Qtconsole can show the outputs of matplotlib embedded inside the window instead of showing as a pop-up. It was a bit pain fixing various python modules that depended upon on other packages in debian. But in Archlinux, a simple ‘pacman -S ipython’ after a system upgrade with ‘pacman -Syu’ solved the issue. (Please note that though ‘pacman -Sy ipython’ alone installs new version of Ipython, it may lead to dependency issues sometimes. Always install with ‘-S’ and have an system upgrade with ‘-Syu’ often). Upgrading the system obviously updates kernel, now Arch has kernel 3.0 in repo!

Please do not have a feeling that I’m saying other distro/package managers are bad or less useful than Arch/pacman, I was simply having a comparison under special conditions – Indeed, every GNU/Linux thing is great and well developed!

Another great feature I found in Archlinux is the rc.conf file. We can easily configure various system wide things in /etc/rc.conf file, like which all kernel modules to load, which all daemons to run at start, hostname, timezone, network interfaces, gateways and so on. There’s also an application called ‘rc.d’ which is similar to ‘service’ in debian/ubuntu using which we can start various services like sshd, etc. Also, the support in IRC channel (#archlinux @ irc.freenode.net) and in Arch forums are very helpful.

Finally, as a student, I find Archlinux very useful and informative, Also it’s so much of fun using it. I humbly recommend this sweet GNU/Linux distro to everyone who likes to add more spice to their GNU/Linux computing. I just started with Archlinux and hope I could post more about it in future. Thank you so much for reading. Greetings!

It was really a wonderful experience at MES :)

Yesterday, I went to MES College of Engineering to deliver a small talk on programming and free software, it was entirely a new experience for me. A bigger crowd than expected was present. It went fine Thanks to Raghesh sir, Raju sir, S@IT and to friends there

I’m happy to share my little slides. It was created according to numerous suggestions by Raghesh sir. For fun, the presentation was started with a SMS trigger from audience The code for that is like ‘get-thing-done’ and doesn’t have the quality to upload. It’s developed using python with gammu module. Please feel free to tell me if you want to have a look at the code.

Attribution: ‘Input -> Fun -> Output’ is an idea got from Niyam Bhushan during his talk at NIT Calicut on FOSS Meet day.

Thank you

C program to extract email IDs from a file

Here’s a small program to extract email IDs from an input file. It could have done using regex (in Python or  in any other high level language), but doing it in C is more fun, eh?

The code is here!

Usage: parseEmail [FILE]

Suggestions and improvements are always welcome Thank you!

A sudoku checking program in C :)

It just started when my younger bro, Shafeeq who reads hacker news everyday, found a little interesting blog post. It was about the authors experience in applying for an internship at Google. The candidate was asked to write a program to check a completed sudoku during the telephone interview  for errors, in his favorite programming language. I asked bro, “Why don’t you give it a try?!”. He’s now in 11th standard and started coding in C++ which he learns in Computer Science subject.  He came up with the code in one day, and then it was my turn to do that Here’s the way I solved the problem and it’s in pure C.

You can find the code here, in github. The input is given as a plain text file that contains 9×9 numbers separated by space. A sample input is given below:

7 2 3 8 4 6 1 5 9
6 1 5 3 9 2 4 7 8
8 4 9 7 1 5 6 3 2
3 7 8 6 5 4 9 2 1
1 9 4 2 8 7 3 6 5
2 5 6 9 3 1 8 4 7
5 6 1 4 7 9 2 8 3
4 8 7 1 2 3 5 9 6
9 3 2 5 6 8 7 1 4

And to check for errors, please call the program with the file as argument, like this -

$checksudoku <data_file>

Hope you enjoyed it, Please go through the code and feel free to post your valuable comments and suggestions here. Thank you

The little twitter client I use :)

Here’s a small python script to update and read tweets from different timelines. You can use it with head/tail commands to customize the output. Actually, I wrote this script just for personal use and now I would like to share it with you Thanks to tweepy python module, make sure it’s installed before trying the script

#!/usr/bin/env python
# Copyright 2011 Ershad K <ershad92@[nospam]gmail.com>
# Licensed under GPL Version 3

import sys
import tweepy

CONSUMER_KEY = ' Fill here'
CONSUMER_SECRET = ' File here too'
ACCESS_KEY = ' Type yours here'
ACCESS_SECRET = 'Type yours here too'

auth = tweepy.OAuthHandler(CONSUMER_KEY, CONSUMER_SECRET)
auth.set_access_token(ACCESS_KEY, ACCESS_SECRET)
api = tweepy.API(auth)

if sys.argv[1] == 'u':
    api.update_status(sys.argv[2])

elif sys.argv[1] == 'p':
    public_tweets = api.public_timeline()
    for tweet in public_tweets:
        print tweet.user.screen_name,":",tweet.text
        print ""

elif sys.argv[1] == 'r':
    mention_tweets = api.mentions()
    for mtweet in mention_tweets:
        print mtweet.user.screen_name,":",mtweet.text
        print ""

elif sys.argv[1] == 'h':
    friends_tweets = api.home_timeline()
    for ftweet in friends_tweets:
        print ftweet.user.screen_name,":", ftweet.text
        print ""

Hope you like it

Python Script to fix VBR errors of mp3 files in a directory, recursively

If the seek bar of your rhythmbox is not working with some mp3 files, it might be an issue with Variable Bit Rate of them. The tool, ‘vbrfix’ written by William Pye solves the issue, but the problem is that it doesn’t have an option to search for files recursively. Here is a small python script that gets the paths of multiple mp3 files recursively and give them as arguments to vbrfix tool. Make sure you install vbrfix (from the software repo) before running the script.

Please see comments for a better, 1 line substitute to do the same. Thanks to Rajeesh ettan and Syam ettan

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
#       vbrfixdir.py
#
#       Copyright 2011 Ershad K <ershad92@gmail.com>     
#
#       Usage: python vbrfixdir.py
#
#       This program is free software; you can redistribute it and/or modify
#       it under the terms of the GNU General Public License as published by
#       the Free Software Foundation; either version 2 of the License, or
#       (at your option) any later version.
#
#       This program is distributed in the hope that it will be useful,
#       but WITHOUT ANY WARRANTY; without even the implied warranty of
#       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#       GNU General Public License for more details.
#
#       You should have received a copy of the GNU General Public License
#       along with this program; if not, write to the Free Software
#       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#       MA 02110-1301, USA.

import sys
import os

quote = '"'
folder = sys.argv[1]
find_command = "find " + folder
find_command += " > mp3files_list"

os.system(find_command)
os.system("sed 1d mp3files_list > mp3files_list1");

f = open("mp3files_list1", 'r')
for line in f:
    line = line[:len(line)-1]
    command = "vbrfix -always "
    command += quote + line + quote
    command += " " + quote + line + quote
    print command
    os.system(command)

os.system("rm mp3files_list mp3files_list1")

Improvements to code and suggestions are always welcome, Happy Hacking

Irssi notification in terminal using ‘write command’

In Desktop Environments like KDE or GNOME, we have special libraries like knotify or libnotify to display notifications from various applications. Some applications like Konversation has its own notification systems. But what about command line tools like Irssi? Imagine you are chatting in tty1 using irssi and doing something in tty2.How will you know if someone has mentioned you nick in channel message? Well, here is a small solution for this.

Luke Macken has written a wonderful  perl script to display notifications using notify-send command in desktop environments. Thanks to open source, I tweaked the call to notify-send command to suit our tty-notification. All that you have to do is this :

Step 1 : Get the Script and write it to a file ‘notify.pl’.

Step 2 : Replace

system(“notify-send -i gtk-dialog-info -t 5000 ‘$dest->{target}’ ‘$stripped’”);

With

system(“echo ‘$dest->{target}’ ‘$stripped’ | write <Your username>”);

Make sure you replace <Your username> with your system username.

Step 3 : Put it in ~/.irssi/scripts/ directory.

Step 4 : Execute the following commands in irssi:

/load perl
/script load notify

Done, you will get notification to the latest tty to which you are logged in!
Good luck

PS: The notification that you get is not eye-candy, please adjust for it now