ZSH autocompletion for tmuxinator

I have been using robbyrussell's Oh My Zsh distribution for a few months now and I feel that it's a very good starting point for ZSH newbies. It's a reasonably good set of plugins, themes and configuration files that makes terminal users' life easier.

Yet another handy tool is tmuxinator which makes using/configuring/starting/managing tmux sessions a cinch. However I found that zsh doesn't have autocompletion for tmuxinator command built-in. And all it'd do when I press 'tab' is list out the files and directory in the current directory. It would be cool if I can make it autocomplete command-line options and project names. And that's what I did this morning.

Here is the piece of code you can put it in file called tmuxinator.plugin.zsh inside custom/plugins/tmuxinator/ directory.

_tmux_cmd() {
  # Constants
  local tmuxinator_configs_path
  tmuxinator_configs_path="$HOME/.tmuxinator"

  local a
  read -l a

  num_args=$(echo "$a" | awk '{print NF}')
  last_arg=$(echo "$a" | awk '{print $NF}')

  if [[ $num_args -le 1 ]]; then
    reply=(start open copy delete implode list doctor help version)
  else
    # whether to autocomplete project names
    if [[ -n "$(echo "start open copy delete" | grep -E "\<$last_arg\>")" ]]; then
      reply=(`ls "$tmuxinator_configs_path" | sed 's/\.yml$//' | sed -e :a -e '$!N; s/\n/ /; ta'`)
    fi
  fi
}

compctl -K _tmux_cmd tmuxinator

Here's how the final outcome looks...

When I enter 'tmuxinator ' and press tab, I'll get this

When it is 'tmuxinator open ' (or start or delete or copy), it'd give

Great!

Split/cut mp3 files using ffmpeg

FFmpeg is a very handy tool. It's hard to find a video/audio encoding/decoding task which it cannot do.  But, with the command-line version one would have to go through the manual page to know about it much better.

Splitting mp3 files is fairly straight forward process.

ffmpeg -i input-file.mp3 -acodec copy -t 00:00:30 -ss 00:02:20 output-file.mp3

This is what I do to extract a 30-second portion (2.20 secs to 2.50 secs) from an mp3 file. Simple!

Ugly-looking gtk3 apps

Often times, using of themes which do not have GTK3 styling in KDE or lightweight desktop environments like Xfce, Openbox and Lxde results in the latest GTK applications like gedit, transmission and evince looking unstyled and ugly.

Here's how my gedit looks like in my Openbox when I use my 'xfce-4.0' gtk2 theme:

So, just copy the default Adwaita theme to your home directory with something like

cp -r /usr/share/themes/Adwaita/gtk-3.0 ~/.config/

After that, edit your ~/.config/gtk-3.0/settings.ini file and insert just the following contents.

[Settings]
gtk-theme-name = Adwaita
gtk-icon-theme-name = fs-icons-ubuntu
gtk-fallback-icon-theme = fs-icons-ubuntu

# next option is applicable only if selected theme supports it
gtk-application-prefer-dark-theme = false

# set font name and dimension
gtk-font-name = Sans 8
gtk-toolbar-style=GTK_TOOLBAR_ICONS
gtk-toolbar-icon-size=GTK_ICON_SIZE_MENU

Add voila, here's how it looks afterwards, (pardon the change in colorscheme of gedit)

Bypass proxy script for Pacman

A few months back I had written a small bash script to bypass the download limit (14MB) imposed by our proxy server. What it essentially does is, downloads files chunk-wise; for instance, in my case, it'd download 14MB chunks at a time and appends it to the file... all on-the-fly! It served me pretty well all these days. Moreover, I also wanted to use it as my Pacman's XferCommand to stay up-to-date.

Though the original version works, it needs a few tweaks. For bigger files, output doesn't look streamlined. Like this...

I removed all unwanted code like i) filename guessing from URLs and ii) output directory validations. And beautified/simplified it's output to look like the below screenshot. To use it with pacman, go to /etc/pacman.conf and add a XferCommand like shown in the top pane of the below screenshot. That's it, now it works well with pacman too...

Here's the new code... It's also on github

#!/bin/bash
#
# Vikas Reddy @
# http://vikas-reddy.blogspot.in/2012/04/bypass-proxy-servers-file-size-download.html
#
#

# Erase the current line in stdout
erase_line() {
    echo -ne '\r\033[K'
}

# Asynchronously (as a different process) display the filesize continously
# (once per second).
# * Contains an infinite loop; runs as long as this script is active
# * Takes one argument, the total filepath
async_display_size() {
    PARENT_PID=$BASHPID
    {
        # Run until this script ends
        until [[ -z "$(ps x | grep -E "^\s*$PARENT_PID")" ]]; do
            # Redraw the `du` line every second
            erase_line
            echo -n "$(du -sh "$1") "
            sleep 1
        done
    }&
    updater_pid="$!"
}

# Defaults
fsize_limit=$((14*1024*1024)) # 14MB
user_agent="Firefox/20.0"


# Command-line options
while getopts 'f:d:u:y' opt "$@"; do
    case "$opt" in
        f) filepath="$OPTARG"    ;;
        u) user_agent="$OPTARG"  ;;
    esac
done
shift $((OPTIND - 1))

# Exit if no URL or filepath argument is provided
if [[ $# -eq 0 ]] || [[ -z "$filepath" ]]; then
    exit
fi

# Only one argument, please!
url="$1"

# Create/truncate the output file
truncate --size 0 "$filepath"


# Asynchronously (as a different process) start displaying the filesize
# even before the download is started!
async_display_size "$filepath"

# infinite loop, until the file is fully downloaded
for (( i=1; 1; i++ )); do

    # setting the range
    [ $i -eq 1 ] && start=0 || start=$(( $fsize_limit * ($i - 1) + 1))
    stop=$(( $fsize_limit * i ))

    # downloading
    curl --fail \
         --location \
         --user-agent "$user_agent" \
         --range "$start"-"$stop" \
         "$url" >> "$filepath" 2> /dev/null; # No progress bars and error msgs, please!

    # catching the exit status
    exit_status="$?"

    if [[ $exit_status -eq 22 ]] || [[ $exit_status -eq 36 ]]; then
        # Download finished
        erase_line
        echo "$(du -sh "$filepath")... done!"
        break
    elif [[ $exit_status -gt 0 ]]; then
        # Unknown exit status! Something has gone wrong
        erase_line
        echo "Unknown exit status: $exit_status. Aborting..."
        break
    fi

done

This can also be used as a standalone script to download files normally. Just that you need to mention the full filepath of where you want to download. Like this...

./pacman-curl.sh -f ~/downloads/video.mp4 'http://the-whole-url/'

TMUX Cheatsheet

TMUX is a fitting competitor to GNU Screen. Here's a cheatsheet of most keybindings. I lifted it straight from its man page.

TMUX Cheatsheet.docx
TMUX Cheatsheet.pdf

VIM Molokai colorscheme

Here’s a screenshot of my gVim…

• Colorscheme: molokai
• Font: Monaco 10pt
• OS: Archlinux
• Resolution: 1280x1024

Archlinux: Compile ffmpeg with nonfree codecs

The ffmpeg binaries that are present in the official repository of Archlinux are not compiled with nonfree codecs. Some excellent ones like libfaac, libx264 and lib-nonfree are not included by default. However, with AUR and its package building automation tool yaourt, one can easily accomplish this. Here are the steps...

1. Install yaourt using pacman -S yaourt, if you haven't already.
2. Key in yaourt -Sb ffmpeg, and answer 'Yes' when asked for confirmation. Remember, you'd have to edit PKGBUILD when asked for. Add --enable-nonfree and --enable-libfaac and other needed configuration options to the build() function, exit the editor, and proceed.
3. That's it, get yourself a cup of tea while the compilation process to finishes, and you're good to go.

PKGBUILD in vim

For a list of available configuration options, see http://git.videolan.org/?p=ffmpeg.git;a=blob;f=configure;h=f30998b37c80ff83a81f4949ea8ab0cfb8043376;hb=HEAD

Wallpaperswide download script in Windows

A few of the visitors of my blog found it difficult to run my wallpapers download script (http://vikas-reddy.blogspot.in/2012/01/script-to-download-wallpapers-from.html) in their Windows OSes. So, here's what I did to run it in my Win XP Pro SP2 (32-bit).

1. Install Ruby 1.9.3-p194 from  http://rubyinstaller.org/downloads/. Normally the defaults are fine. I installed it to my "C:\" folder
2. Install nokogiri gem using "C:\Ruby193\bin\gem" install nokogiri
3. Install wget from  http://gnuwin32.sourceforge.net/packages/wget.htm. Keep the defaults, or else, change the "wget" line in the script to reflect the correct executable path.
4. Download the following code into a file named wallpaperswide-script.rb, and adjust Resolution and OutputDirectory variables. It's 1600x900 and "C:\Wallpapers" respectively by default. Check out the original post for available resolutions.
5. Run it using "C:\Ruby193\bin\ruby.exe" "C:\wallpaperswide-script.rb"
6. That's it, all your wallpapers will get downloaded into the given folder.

require 'open-uri'
require 'nokogiri'

Resolution = "1600x900"
Base_URL   = "http://wallpaperswide.com/#{Resolution}-wallpapers-r/page/"
Output_Directory = "C:\\Wallpapers"


(1..2805).each do |page_num|

  # Go page by page
  url = Base_URL + page_num.to_s

  # Parse html
  f = open(url)
  doc = Nokogiri::HTML(f)

  # Loop over image-boxes
  doc.css("div.thumb").each do |wallp|

    # Extract wallpaper subpage url
    wallp.css("div[onclick]").attr("onclick").value =~ /prevframe_show\('(.*)'\)/
    subpage_url = $1
    subpage_url =~ %r|http://wallpaperswide\.com/[^/]+/([\w\d]+)\.html|

    # Generate url of the required wallpaper
    wallp_url = %|http://wallpaperswide.com/download/#{$1}-#{Resolution}.jpg|
    
    # Download... with a user-agent parameter just in case...
    # use '--limit-rate=100k' to limit download speed
    system(%|"C:\\Program Files\\GnuWin32\\bin\\wget.exe" -c -U "Firefox/4.5.6" -P "#{Output_Directory}" "#{wallp_url}"|)

  end
end

I'm continually working on it. You can find the latest version of the code on my github account.


The below listed screenshots will guide you through the process...

Convert videos using ffmpeg to watch in Nokia 5230 / 5233 / 5800 / 5530 / X6 / N97

Nokia 5230/5800/.../X6 are (err... were) great smartphones. At least before the advent of the now-ubiquitous Android/Windows ones. They have got excellent, high resolution (640x360) screens which are great for watching videos on the go.

ffmpeg too has become the de facto encoding suite for converting videos, at least on linux. Here are the ffmpeg commands used to convert videos to a format which the aforementioned devices play without a hiccup. My 5230 plays MPEG4 videos encoded with lavc/xvid upto resolution 640x360. However, it'd play videos encoded with the advanced H264 codec only upto 320x240.

# ffmpeg libxvid
 ffmpeg -i Input-Filename.avi -f mp4 -y \
   -vcodec libxvid -b:v 600k -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
   -r 25 -s 640x272 -aspect 640:360 -vf pad=640:360:0:44 \
   -threads 2 -async 1 -pass 1 /dev/null
 ffmpeg -i Input-Filename.avi -f mp4 \
   -y -vcodec libxvid -b:v 600k -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
   -r 25 -s 640x272 -aspect 640:360 -vf pad=640:360:0:44 \
   -threads 2 -async 1 -pass 2 ./Input-Filename-ffmpeg.mp4

# ffmpeg libx264
 ffmpeg -i Input-Filename.avi -f mp4 -y \
   -vcodec libx264 -b:v 600k -vpre ipod320 -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
   -r 25 -s 320x196 -aspect 320:240 -vf pad=320:240:0:22 \
   -threads 2 -async 1 -pass 1 /dev/null
 ffmpeg -i Input-Filename.avi -f mp4 -y \
   -vcodec libx264 -b:v 600k -vpre ipod320 -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
   -r 25 -s 320x196 -aspect 320:240 -vf pad=320:240:0:22 \
   -threads 2 -async 1 -pass 2 ./Input-Filename-ffmpeg.mp4

However, for batch processing and automation, a handy Bash shell script would be great. This is a small script I use to convert my videos. (Note: I'm continually working on it. The latest code will be on my github account)

#!/bin/bash
#
#    Vikas Reddy @ http://vikas-reddy.blogspot.com/
#
# ffmpeg libxvid
# --------------
# ffmpeg -i Input-Filename.avi -f mp4 -y \
#   -vcodec libxvid -b:v 600k -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
#   -r 25 -s 640x272 -aspect 640:360 -vf pad=640:360:0:44 \
#   -threads 2 -async 1 -pass 1 /dev/null
# ffmpeg -i Input-Filename.avi -f mp4 \
#   -y -vcodec libxvid -b:v 600k -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
#   -r 25 -s 640x272 -aspect 640:360 -vf pad=640:360:0:44 \
#   -threads 2 -async 1 -pass 2 ./Input-Filename-ffmpeg.mp4
#
# ffmpeg libx264
# --------------
# ffmpeg -i Input-Filename.avi -f mp4 -y \
#   -vcodec libx264 -b:v 600k -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
#   -r 25 -s 320x196 -aspect 320:240 -vf pad=320:240:0:22 \
#   -threads 2 -async 1 -pass 1 /dev/null
# ffmpeg -i Input-Filename.avi -f mp4 -y \
#   -vcodec libx264 -b:v 600k -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
#   -r 25 -s 320x196 -aspect 320:240 -vf pad=320:240:0:22 \
#   -threads 2 -async 1 -pass 2 ./Input-Filename-ffmpeg.mp4
#  
#  Usage
#  -----
#  Command-line options: 
#  -a : Video aspect ratio. Could be either 1.66 or 2.35 (default)
#  -b : Video bitrate. Should be in the form of 600k (default)
#  -c : Video codec. Should be either libx264 or libxvid (default)
#  -d : Output directory. Current directory (.) is the default
#  -y : Whether to ask confirmation before overwriting any file.
#       Should be either "yes" (default) or "no"
#  
#  Examples
#  --------
#  1) ./ffmpeg-encode.sh The.Movie.Filename.avi 
#     would output the xvid-encoded video to The.Movie.Filename-ffmpeg.mp4 in the current directory
#  2) ./ffmpeg-encode.sh -a 1.66 -b 650k -c libx264 -d /home/vikas/downloads/ -y The.Movie.Filename.avi 
#  


# Command-line options
while getopts 'a:b:c:d:o:p:y' opt "$@"; do
    case "$opt" in
        a) video_aspect="$OPTARG" ;;
        b) vbitrate="$OPTARG" ;;
        c) video_codec="$OPTARG" ;;
        d) output_dir="$OPTARG" ;;
        o) addl_options="$OPTARG" ;;
        p) passes="$OPTARG" ;;
        y) ask_confirmation="no" ;;
    esac
done
shift $((OPTIND - 1))


# Defaults
video_aspect="${video_aspect:-2.35}"
video_codec="${video_codec:-libxvid}" # or libx264
vbitrate="${vbitrate:-600k}"
passes="${passes:-2}"
output_dir="${output_dir:-.}"


vpre_pass1=""
vpre_pass2=""

if [[ "$video_codec" == "libx264" ]]; then
    #vpre_pass1="-vpre fastfirstpass -vpre baseline"
    #vpre_pass2="-vpre hq -vpre baseline"
    aspect="320:240"

    if [[ "$video_aspect" == "2.35" ]]; then
        resolution="320x196"
        pad="pad=320:240:0:22"
    elif [[ "$video_aspect" == "1.66" ]]; then
        resolution="320x240"
        pad="pad=320:240:0:0"
    fi;

elif [[ "$video_codec" == "libxvid" ]]; then
    aspect="640:360"

    if [[ "$video_aspect" == "2.35" ]]; then
        resolution="640x272"
        pad="pad=640:360:0:44"
    elif [[ "$video_aspect" == "1.66" ]]; then
        resolution="640x360"
        pad="pad=640:360:0:0"
    fi;
fi;


echo "Encoding '${#@}' video(s)";

for in_file in "$@"; do

    # If the filename has no extension
    if [[ -z "$(echo "$in_file" | grep -Ei "\.[a-z]+$")" ]]; then
        fname="$(basename "${in_file}")-ffmpeg.mp4"
    else
        fname="$(basename "$in_file" | sed -sr 's/^(.*)(\.[^.]+)$/\1-ffmpeg.mp4/')"
    fi
    out_file="${output_dir%/}/${fname}"

    # Avoid overwriting files
    if [[ "$ask_confirmation" != "no" ]] && [[ -f "$out_file" ]]; then
        echo -n "'$out_file' already exists. Do you want to overwrite it? [y/n] "; read response
        [[ -z "$(echo "$response" | grep -i "^y")" ]] && continue
    fi

    # 1st pass
    ffmpeg -i "$in_file" \
           -f mp4 -y $addl_options \
           -vcodec "$video_codec" -b:v "$vbitrate" \
           -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
           -r 25 -s "$resolution" -aspect "$aspect" -vf "$pad" \
           -threads 2 -async 1 -pass 1  \
           "/dev/null"; # $out_file;

    # 2nd pass
    ffmpeg -i "$in_file" \
           -f mp4 -y $addl_options \
           -vcodec "$video_codec" -b:v "$vbitrate" \
           -acodec libfaac -b:a 96k -ac 2 -ar 44100 \
           -r 25 -s "$resolution" -aspect "$aspect" -vf "$pad" \
           -threads 2 -async 1 -pass 2  \
           "$out_file";
done

Its usage is simple too. Without having to remember, edit and type in the lengthy ffmpeg command, this one makes my life a lot easier.

To start with, without any command-line options, the given file is assumed to be of 2.35 (cinema scope) aspect ratio, and consequently encoded using libxvid library to produce a nice 640x360 mp4 video. See below...

A small documentation with available command-line options and a few examples is bundled in the script itself.

NOTE: Because of licensing issues, ffmpeg binaries that are available on the repositories of most of the linux distros are not compiled with "non-free" codec support. This is especially true in the case of libx264 and libfaac. You may have to abandon them and compile the software from sources. Google it!

Do post your views in the comments section below...

My Archlinux screenshot

This is a screenshot of my Archlinux installation. I have been using it since 2007. Since it's a rolling distribution, I'd never ever need to re-install it again. And I've ported/copied this installation to many other machines with all the packages/settings/configuration intact.

The desktop consists of:

1. Xfce 4.10
2. Conky 1.9.0
3. XfPanel, for which no screenspace is reserved. This is great for conserving desktop realestate!
4. Iconset: Faience-Claire
5. A 1280x800 wallpaper from wallpaperswide.com

Bypass proxy server's file size download limit restriction

   Many organizations and colleges restrict their employees and students respectively from downloading files from the Internet which are larger than a prescribed limit. It is way too low at 14MB where I work. Fret not! There are ways to bypass this. And here is a simple bash script I wrote to download much larger files at my workplace.

Note: This script works only with direct links and with servers which support resume-download functionality.

  I'm continually working on it. So, the latest version will be available on my github account.

How to run it?

1. Download the following code to a text file named curldownload.sh
2. Give executable permissions to it chmod +x curldownload.sh
3. File size limit, fsize_limit variable, is set to 14MB. You may change it to your liking.
4. The script takes two arguments; the first one being the url of the file to be downloaded; the second one which is optional (defaults to "./") is the output directory.
5. For ex:- ./curldownload.sh http://ftp.jaist.ac.jp/pub/mozilla.org/firefox/releases/12.0/linux-i686/en-US/firefox-12.0.tar.bz2 "$HOME/Downloads"
6. A little more complex example of it using multiple urls, and two command-line arguments (-d for output directory, and -u for user-agent http header) is:  ./curl-multi-url.sh -d ~/downloads/ -u "Chromium/18.0" http://ftp.jaist.ac.jp/pub/mozilla.org/firefox/releases/11.0/linux-x86_64/en-US/firefox-11.0.tar.bz2 http://ftp.jaist.ac.jp/pub/mozilla.org/firefox/releases/12.0/linux-i686/en-US/firefox-12.0.tar.bz2

#!/bin/bash
#
# Vikas Reddy @
#   http://vikas-reddy.blogspot.in/2012/04/bypass-proxy-servers-file-size-download.html
#
# 
# Usage:
#     ./curl-multi-url.sh -d OUTPUT_DIRECTORY -u USER_AGENT http://url-1/ http://url-2/;
#     Arguments -d and -u are optional
#
#

# Defaults
fsize_limit=$((14*1024*1024))
user_agent="Firefox/10.0"
output_dir="."


# Command-line options
while getopts 'd:u:' opt "$@"; do
    case "$opt" in
        d) output_dir="$OPTARG";;
        u) user_agent="$OPTARG";;
    esac
done
shift $((OPTIND - 1))


# output directory check
if [ -d "$output_dir" ]; then
    echo "Downloading all files to '$output_dir'"
else
    echo "Target directory '$output_dir' doesn't exist. Aborting..."
    exit 1
fi;


for url in "$@"; do
    filename="$(echo "$url" | sed -r 's|^.*/([^/]+)$|\1|')"
    filepath="$output_dir/$filename"

    # Avoid overwriting the file
    if [[ -f "$filepath" ]]; then
        echo -n "'$filepath' already exists. Do you want to overwrite it? [y/n] "; read response
        [ -z "$(echo "$response" | grep -i "^y")" ] && continue
    else
        cat /dev/null > "$filepath"
    fi

    echo -e "\nDownload of $url started..."
    i=1
    while true; do   # infinite loop, until the file is fully downloaded

        # setting the range
        [ $i -eq 1 ] && start=0 || start=$(( $fsize_limit * ($i - 1) + 1))
        stop=$(( $fsize_limit * i ))

        # downloading
        curl --fail --location --user-agent "$user_agent" --range "$start"-"$stop" "$url" >> "$filepath"

        exit_status="$?"

        # download finished
        [ $exit_status -eq 22 ] && echo -e "Saved $filepath\n" && break

        # other exceptions
        [ $exit_status -gt 0 ] && echo -e "Unknown exit status: $exit_status. Aborting...\n" && break

        i=$(($i + 1))
    done
]]>

Port your GTalk contacts to another account

Porting your GTalk contacts to another GTalk account is not as easy as the export-import feature of Gmail Contacts would have you believe. For, your GTalk accounts are only a subset of your Gmail ones. So, essentially, if you'd export all your contacts to a csv file from your Account #1 and import them to your Account #2, they would get imported but do not appear in your Gtalk.

I've been using Pidgin since many years now and I never knew it'd store all the contacts it imported in an xml file locally, with groups they belong to, their buddy icons, last seen time, etc.,  ~/.purple/blist.xml is where all these are present.

Steps


1. Install Pidgin, create accounts for both your gmail ids.
2. Open your Ruby console/irb and run the following code

# Parse the xml document...
doc = REXML::Document.new(File.read("/home/YOUR_USERNAME/.purple/blist.xml"))

# Initialize empty arrays
contacts_1 = []
contacts_2 = []

# Get all your contacts in your account number 1, assume it as account_1@gmail.com
doc.elements.each('//buddy[starts_with(@account,"account_1@gmail.com")]/name') {|e| contacts_1 << e.text}

# Get all your contacts in your account number 2, assume it as account_2@gmail.com
doc.elements.each('//buddy[starts_with(@account,"account_2@gmail.com")]/name') {|e| contacts_2 << e.text}

# Get the email ids of all contacts which are present in account#2 but not in account#2
# i.e., the contacts who need to be invited
(contacts_2 - contacts_1).join(", ")

3. You'll get some thing like this as output of the last line of code...

4. multiple contacts can be invited at once using Windows GTalk. So, open it and paste this output into the Invite Contacts wizard as shown below

That's it! You have the requests sent to all your invitees from your new account.

cp: An amazing swiss knife of GNU

  The other day I was banging my head wondering how to infuse life (read, extra space) into my ageing laptop and into the Arch Linux installation, which, by the way, is turning five this year. The rolling release model and its light-weight packaging has bitten me way back in 2007. I had used my old 80GB, Turion 64x2, 1.5GB DDR2 Presario V3029AU to the maximum, and it's showing.

   Last week, I tried to install Oracle 10g XE on Fedora 16 and it asked for a minimum of 1024MB of swap, a whisker short of what my harddisk actually had. So, I was only left with one dreaded option: to re-format my internal drive and to make space for three Linux distros and a Windows 7 x64 primary partition with sufficient swap space. For that, I had to retain the contents of my Arch. A few options I found after scouting the Internet were:

1. Use dd to take an as-is backup of the partition to an image file
2. Use clonezilla to take backup to an image file
3. Use partimage
4. Use cp to simple copy all the files onto a separate "linux-compatible" filesystem (read, one which retains the permissions and ownership of the files)

  Obviously, as my main intention was to expand in-place the partition or move files onto a bigger partition, the first option was ruled out. Clonezilla had to be used by burning the live iso  onto a CD or a pen drive. The only sensible option I was left with was to use cp.

cp -ax /source-path/* /destination-path/

   Mind you, I didn't know what all cp could do even after using it for the past seven years on a daily basis. This command simply copies all the files onto the new partition, of course, with all the necessary bells and whistles such as permissions, file ownership and other necessary attributes. Note the two command-line options "-a" and "-x". The latter is to indicate to cp that only one file system needs to be copied. Ignoring this option will end you up with copies of files present on mounted partitions too on your new partition. These two options are absolutely essential for your new partition to work as intended.

  This left me with sufficient space (13GB each) for Arch , LMDE and Fedora 16.

  This scenario reinforces the simplicity of design and everything-is-transparent-to-user philosophy of GNU/Linux. And, cp truly is an amazing swiss knife of it!

A simple command-line Megaupload download manager

Have a bunch of megaupload links and ever felt the need for a simple, lightweight, text-based/command-line and eminently extensible script which does all the downloading for you?

Your search ends here!

Requirements

1. wget: which is present by default in almost linux distros
2. ruby and nokogiri: These can be installed as shown here.

Steps

1. Save the script as megaupload_dm.rb
2. Make it executable using chmod +x megaupload_dm.rb
3. Install the dependencies
4. Dump all your megaupload links to a file named megaupload_list.txt in the current directory. You can also insert any content or comments in this file
5. Tweak the LinkFile and OutputDirectory variables to your liking.
6. Limit the download rate by adding --limit-rate=100k to the wget command at line #43 (optional)
7. Run it using ./megaupload_dm.rb
8. Your files are downloaded to ~/Downloads directory!

#!/usr/bin/env ruby


# Is the url a valid one?
def valid?(url)
  url =~ %r|^http://www.megaupload.com/\?d=[a-zA-Z0-9]+$|
end

require 'rubygems'
require 'nokogiri'
require 'open-uri'

LinkFile = "./megaupload_list.txt"
OutputDirectory = "/home/vikas/Downloads"
TempFile = "/tmp/megaupload-tmp.html"


File.open(LinkFile, 'r') do |f|
  f.each_line do |link|

    link.strip!

    next unless valid?(link)

    begin

      puts "Fetching information for #{link} ..."
      `wget "#{link}" -U "Firefox/4.0.0" --quiet --output-document #{TempFile}`

      doc = Nokogiri::HTML(File.read(TempFile))

      # Filename and Direct Link
      fname = doc.css("div.downl_main div.download_file_name").first.content
      direct_link = doc.css("div.downl_main div.download_member_bl a").last.attributes['href'].value

      # Actual download
      puts "Downloading #{fname} ... \n"
      `wget -c -P "#{OutputDirectory}" -U "Firefox/3.6.3" "#{direct_link}"`
      puts "*********************************** DONE *******************************************"
      puts "\n\n"

      # Sleep 5 secs. Take some load off megaupload ;)
      sleep 5

    rescue
      puts "ERROR! FileNotFound or otherwise; Skipping this file...."
      puts "\n\n"
      next
    end

  end
end

A script to download wallpapers from wallpaperswide.com

Going through wallpapers websites like http://www.wallpaperswide.com/ and ever wondered how cool would it be if you have a magic wand with which you could download all the wallpapers without having to manually download the ten images in all of the 2500-odd pages?

Your search ends here!

Dependencies

1. This script is written in Ruby. Most Linux distros ship a basic version of this scripting language. If not, install it along with rubygems using the following commands.
2. This script needs wget utility to download. wget is shipped with almost all linux distros. If not, install it using your distro's package manager.

# If you don't use a Debian-based distro like Ubuntu or Linux Mint, replace 'apt-get' with your distro's package manager

# Install 'ruby' and 'rubygems' if not already installed
sudo apt-get install ruby rubygems

# Install 'wget' if not installed
sudo apt-get install wget

# Install 'nokogiri' gem
gem install --no-r{doc,i} nokogiri

1. Save the following ruby code into a file named wallpaperswide_dot_com.rb
2. Choose the resolution of the wallpapers you want to download. The list of resolutions supported are given in the beginning of the script. Tweak Resolution variable accordingly.
3. Adjust the Output_Directory variable.
4. Run the script by ruby wallpaperswide_dot_com.rb
5. It'll be a 2+GB download depending on the resolution. If you desire to limit your download speed to say 100kbps, you could add an additional argument to the wget command (the third line from the end) like wget -c --limit-rate=100k -U "Firefox/4.5.6" ...;

#!/usr/bin/env ruby
#
#  Vikas Reddy
#
#  A little script to download ALL the wallpapers of a given
#  resolution from http://www.wallpaperswide.com/
#
#  Requirements
#  ============
#  Ruby Version: 1.9.2
#  Gems: nokogiri, open-uri
#  Other programs: wget
#
#
#  Available Resolutions
#  =====================
#
#  Wide
#  
#  * 16:10 960x600
#  * 16:10 1152x720
#  * 16:10 1280x800
#  * 16:10 1440x900
#  * 16:10 1680x1050
#  * 16:10 1920x1200
#  * 16:10 2560x1600
#  * 16:10 3840x2400
#  * 16:10 5120x3200
#  * 5:3 800x480
#  * 5:3 1280x768
#  
#  HD
#  
#  * 16:9 960x540
#  * 16:9 1024x576
#  * 16:9 1280x720
#  * 16:9 1366x768
#  * 16:9 1600x900
#  * 16:9 1920x1080
#  * 16:9 2048x1152
#  * 16:9 2400x1350
#  * 16:9 2560x1440
#  * 16:9 3554x1999
#  * 16:9 3840x2160
#  
#  Standard
#  
#  * 4:3 800x600
#  * 4:3 1024x768
#  * 4:3 1152x864
#  * 4:3 1280x960
#  * 4:3 1400x1050
#  * 4:3 1440x1080
#  * 4:3 1600x1200
#  * 4:3 1680x1260
#  * 4:3 1920x1440
#  * 4:3 2048x1536
#  * 4:3 2560x1920
#  * 4:3 2800x2100
#  * 4:3 3200x2400
#  * 4:3 4096x3072
#  * 5:4 1280x1024
#  * 5:4 2560x2048
#  * 5:4 3750x3000
#  
#  Mobile Ratio
#  
#  * VGA 240x320
#  * VGA 480x640
#  * VGA 320x240
#  * VGA 640x480
#  * WVGA 240x400
#  * WVGA 480x800
#  * WVGA 400x240
#  * WVGA 800x480
#  * HVGA 320x480
#  * HVGA 480x320
#  * HVGA 640x960
#  * HVGA 960x640
#  * iPad 1024x768
#  * iPad 768x1024
#  * HD 16:9 480x272
#  * HD 16:9 272x480
#  * Phone 176x220
#  * Phone 220x176
#  
#  Dual
#  
#  * 4:3 1600x600
#  * 4:3 2048x768
#  * 4:3 2304x864
#  * 4:3 2560x960
#  * 4:3 2800x1050
#  * 4:3 2880x1080
#  * 4:3 3200x1200
#  * 4:3 3360x1260
#  * 4:3 3840x1440
#  * 4:3 4096x1536
#  * 4:3 5120x1920
#  * 4:3 5600x2100
#  * 4:3 6400x2400
#  * 4:3 8192x3072
#  * 5:4 2560x1024
#  * 5:4 5120x2048
#  * 5:4 7500x3000
#  * 5:4 10240x4096
#  * 16:10 1920x600
#  * 16:10 2304x720
#  * 16:10 2560x800
#  * 16:10 2880x900
#  * 16:10 3360x1050
#  * 16:10 3840x1200
#  * 16:10 5120x1600
#  * 16:10 7680x2400
#  * 16:10 10240x3200
#  * 5:3 1600x480
#  * 5:3 2560x768
#  * 16:9 1920x540
#  * 16:9 2048x576
#  * 16:9 2560x720
#  * 16:9 3200x900
#  * 16:9 3840x1080
#  * 16:9 4096x1152
#  * 16:9 4800x1350
#  * 16:9 5120x1440
#  * 16:9 7108x2000
#  * 16:9 7680x2160
#  * 3:2 2880x960
#  * 3:2 4000x1333
#  * 3:2 2304x768
#  
#  Other
#  
#  * 3:2 1152x768
#  * 3:2 1440x960
#  * 3:2 2000x1333


require 'open-uri'
require 'nokogiri'

Resolution = "1600x900"
Base_URL   = "http://wallpaperswide.com/#{Resolution}-wallpapers-r/page/"
Output_Directory = "/home/vikas/Wallpapers/"

# Create the Output_Directory if needed
`mkdir -p "#{Output_Directory}"`

(1..2492).each do |page_num|

  # Go page by page
  url = Base_URL + page_num.to_s

  # Parse html
  f = open(url)
  doc = Nokogiri::HTML(f)

  # Loop over image-boxes
  doc.css("div.thumb").each do |wallp|

    # Extract wallpaper subpage url
    wallp.css("div[onclick]").attr("onclick").value =~ /prevframe_show\('(.*)'\)/
    subpage_url = $1
    subpage_url =~ %r|http://wallpaperswide\.com/[^/]+/([\w\d]+)\.html|

    # Generate url of the required wallpaper
    wallp_url = %|http://wallpaperswide.com/download/#{$1}-#{Resolution}.jpg|
   
    # Download... with a user-agent parameter just in case...
    # use '--limit-rate=100k' to limit download speed
    `wget -c -U "Firefox/4.5.6" -P "#{Output_Directory}" "#{wallp_url}"`
  end
end

A script to compile a latex-beamer presentation into all themes

I always wondered how great and handy would it be had I had a nifty script to compile my latex presentation using all the themes present in my current tex installation so that I can have a look at all the output files and choose the one which looks best.

And, this is the little bash shell script I've written to fulfill my need.

1. Save this script into your Latex project directory
2. Adjust the variables listed in the script to your liking ($themes_path and $output_directory)
3. Give executable permission using "chmod +x $filename" or otherwise
4. Execute it! It takes your ".tex" as the command-line argument and outputs the pdfs into a directory named "change_themes". There will be as many themes as your Beamer installation could possibly output.

PS: It'll not disturb/write to your original .tex file though. It just reads it.

#!/bin/bash

themes_path="/usr/share/texmf/tex/latex/beamer/base/themes/theme"
filename="$1"
output_directory="./change_themes"

# Needs the .tex file as the command-line argument
if [[ -z "$filename" ]]; then
    echo "Needs a command-line argument";
    exit;
fi

# Create the output directory if needed
if ! [[ -d "$output_directory" ]]; then
    mkdir -p "$output_directory";
fi

for theme in $themes_path/*.sty; do
    theme_name="$(echo "$(basename "$theme")" | sed -re 's/beamertheme(.*)\.sty/\1/')"
    sed -r "s/usetheme\{(.*)\}/usetheme{$theme_name}/" "$filename" > "$output_directory/$filename"
    pdflatex -output-directory="$output_directory" "$output_directory/$filename"
    pdf_fname="$(basename "$filename" ".tex").pdf"
    pdf_fname_new="${theme_name}_${pdf_fname}"
    mv "$output_directory/$pdf_fname" "$output_directory/$pdf_fname_new"
done

Kerala Trip

Many of my friends advised me to start writing a blog. So, this is my first post of my first blog and I decided to write it about my Kerala trip that we five of us undertook. Main aim of this post is to serve as a trip report to me (which will be useful for future reference) and to help others (may help as an itinerary also!) who also want to go on such trips. It is almost three months since we were on this trip and I'll recollect as much as possible. Please read on and do not forget to leave a comment...

Kerala Trip

A batch trip of UG3 was planned as soon as Felicity 2008 was finished. Travel plan was to visit Ooty and Munnar from 3rd April to 8th April, 2008. I was too excited and started dreaming about it after seeing some photographs of Munnar on the Internet. But my excitement didn't last long. As there weren't sufficient number of students enrolled, the trip got cancelled. But I don't want to give up and started thinking of alternatives. So, I starting gathering people who were interested in the tour. I knew Shashank is always with me (Ask him whatever question you want, his reply is always "YES"). Soon, Vinay and Raju joined us. It took us some time and effort to convince Vimjam.
Since the (trip) proposal was mine, I was bestowed with the job of planning the itinerary and come up with an approximate estimate amount of money required. We don't want to make it more than Rs. 5000/- per person. Initially, our plan was to visit Ooty and Munnar (similar to the batch trip) but Ooty somehow got cancelled upon advice by Bhargava (a good friend of mine who is from Tamil Nadu) that April was "season" for Ooty and as we are not booking rooms before hand online, finding accommodation there is quite tough. As Vinay is quite interested in going to a beach, with the help of other friends I modified the tour plan. So, now the plan was to visit Munnar, Aleppey and Kochi. Soon, I started on a mission to convince and gather many other friends to join us for the tour. My efforts foundered; for some people time was the problem and money for others. At last, I went to Nampally railway station with Ravindra (Kam) to book tickets for our tour ("Hyderabad to Coimbatore: Sabari Exp" on 3rd April and "Ernakulam Jn. to Hyderabad: Sabari Exp" on 9th April) on second week of March.
I was so excited that I couldn't even wait for a single day for that elusive 3rd April -- which is still three weeks away. That three weeks looked like 3 light years for me. I just couldn't explain in words how excited and restless I felt at that time. Even that fast approaching End Semester Examinations didn't deter me and in the week before the exams, I (literally) used to dream about the trip. After much suffering, somehow the exams are over and Shashank, Vinay and me went home.

3th April, 2008
Somehow that "elusive" 3rd April did come and I already packed my luggage the previous day. Shashank, Vinay and me reached Nampally railway station at 11.00 a.m. on an auto rickshaw. Although our train (Sabari Express) is there on the platform, we didn't notice it. We boarded the train at 11.45 a.m. and it started at its scheduled departure time -- 12.00 noon. Raju and Vimjam joined us at Secunderabad. Since two of the seats beside us are empty, we were able to stretch our muscles and relax (anything better than getting cramped is relaxing ... :-)). We soon had our lunch (yummy Egg fried rice and pulihora: home made) and all of us were enjoying the train journey. But the worse thing is yet to come. It is already 2 p.m. and we were feeling the mid-summer heat of 40+ degrees . It soon became uncomfortable and unbearable and all that we could do was "nothing". Though we had litres of chilled water and cool drinks, they just weren't enough and brought no respite from the sweltering heat. Vinay and me sat near the door of the bogie for three good hours and the remaining three played chits :-). Added to these, Vinay's mobile ran out of juice in no time and we had no other option but to switch it off.
The train reached Guntur at 6.30 p.m., one hour behind schedule. Since the diesel engine of our train is replaced by an electric one at Guntur and it takes good amount of time for shunting, we had a 30 min.s halt there. We asked Vimjam to look after the luggage, wen't out for a stroll on the platform and had some fruit juices. In mean time Vimjam was given a small bag of cotton sample by a stranger to be delivered at Coimbatore (Since Vimjam is also from Guntur district, పాపం దీన్నే అంటారేమో "ప్రాంతీయ అభిమానం" అని). Vinay, especiallay, was very angry with Vimjam. Within no time, the train reached Ongole (8 p.m.) and we had our dinner (homemade Hot Chapati with Potato curry-- packed in Aluminium foils, so they're still hot). I was really excited and started putting my nose out of the window :-) when Raju told that a foul smell comes from the industries nearby the railway tracks after the Singarayakonda station (He was familar with that place). Nothing such happened and I was disappointed. Then came Nellore (9 p.m.). We tried to sleep but couldn't because of the heat. Vinay and me were sharing the passage side seats. Soon, we reached Tirupati at 12.30 a.m. and we both woke up because of the ultra-loud announcements in the railway station. I went to my berth and slept at 2.00 a.m.

4th April, 2008
Woke up at 7 a.m. before Salem station, had tea, reached Erode at 8.30 a.m. and the train stopped there for about 45 min.s because someone died on our train. At last reached Coimbatore at 10.30 a.m. just 2 hrs behind schedule. We went to Ukkadam bus stand to board a bus to Udumalpet. Since I can read Tamil, we managed to take the correct bus. Otherwise we would have got f***ed up. Soon we reached Udumalpet at 12.00 noon and had some puffs and fruit juices there. We couldn't dare try a Tamil Nadu thali :-) Boarded a bus to Munnar at 1 p.m. We unpacked our cameras and started clicking pics of the fast approaching Western Ghats. Our attempts to take photographs from the moving bus proved futile -- only few of them came out unblurred. Within few minutes we were inside the thick forest and we all were super-excited. Our bus stopped at Maraiyoor for about 15 min.s, clicked some pics there and started again. The journey till here was wonderful amidst forests. But the real thing is yet to come. Soon, tea plantations started to appear and altitude is rising steadily and we were able to notice the dripping temperatures. I was never been on such a wonderful route. It was like going into refrigerator (Western Ghats) from an oven (Tamil Nadu plains). Western Ghats were at their best. We reached Munnar at 5 p.m. Though the bus journey was nearly 4 hrs, we didn't feel that burden as route was awesome. We got down at Munnar bus stand and were looking for the accommodation. An auto-driver promised to arrange us some good accommodation provided we gave him Rs. 20/- That's dead cheap, isn't it? He took us to a lodge just 50 mts away and there came a steep slope. We need to get down as that auto couldn't climb such a steep slope. After seeing a couple of rooms, we finalized on one after brief negotiation. It was Rs.700/- per day with hot water, TV, etc., After two days of journey, we were completely tired and took rest after having some good dinner in Saravan Bhavan.


5th April, 2008
We woke up at 7 a.m., had breakfast and went to hire a jeep for the site seeing. After a brief negotiation, we agreed on a fare of Rs.900/-. We went to Madupetti side and Cochin side on this day for site seeing. In the "morning session", we went to the following places

1. Photo Point
2. Madupetti dam: speed boating
3. Echo Point
4. Kundala Lake: pedal boating, horse riding
5. Flower park

This being the first day of our site-seeing, we got to face a new challenge; -- Raju's undiscovered passion to get photographed at each and every spot in unusual poses. Four of us were shocked to see Raju's artistic creativity.
And in the "evening session" we went to

1. Atukkad Waterfalls: clicked some pics, had some cool drinks and coffee made with honey. We discovered a dog lover in Shashank here.
2. Pothamedu View Point: clicked some pics and had ginger flavoured local tea.
3. Blossom Park: clicked some pics, played there to our heart's content

In the evening, we talked to some Jeep-drivers regarding a trip to Thekkadi (100 kms. from Munnar, popular for wildlife watching boat ride) for the next day. Since we don't have sufficient time, we had to cancel that trip. Shashank, Vinay and Raju were also interested in a early morning trekking trip and somehow, this too didn't materialized. When we went into the town to buy some tea powder, Vimjam found a Balayya fan in the shop-keeper and began discussing about his films. In the mean time, that guy managed to sell few kilograms of tea powder to him (బాలయ్యబాబు పేరు చెప్పి వాడికి అవసరంలేనివి అంటగట్టాడు). Had some biryani for dinner and went to bed after watching some cricket highlights on the TV.

6th April, 2008
Woke up at 7 a.m., had breakfast and went for site seeing -- this time too by hiring a Jeep. We went to Thekkady side and Coimbatore side for site-seeting this day. In the morning we went to

1. Lockhardt Gap
2. Anairangal Dam
3. Anairangal Reservoir

Vimjam telling some "stories" to the driver

had south indian meals with fish curry for lunch and in the evening, we went to

1. Eravikulam National Park
2. Anaimudi

Purchased some flavored tea en route to our hotel at KDHP tea factory. Since this is our last day in Munnar, we went out for a leisure walk into the town, clicked some pics and bought Tea, Coffee, Spices, Homemade chocolates, etc., which are special and inexpensive here. We even visited Munnar Mela 2008, an annual exhibition of Munnar. Had special Kerala porotta and Egg curry for dinner, packed our luggage (as we need to checkout of the hotel tomorrow morning) and went to bed.

7th April, 2008
Woke up at 5.30 a.m. (very chilling weather; చలి దంచేసింది), took shower, had breakfast and boarded a bus to Kochi. This route was like going into oven from refrigerator. We reached Ernakulam (Ernakulam and Kochi are like twin cities) bus station at 12 noon, hired an auto rickshaw, went to a hotel and checked into two air-conditioned rooms (with a very hight humidity and in mid summer, living in non a/c rooms is like a torture). Freshed-up, had some rubbery fish biryani with pineapples (pineapples in biryani....What the hell was that?? so-called Kerala cuisine) for lunch and after a short nap, we left the hotel to go to Cherai Beach. After one hour journey in city buses, we reached Cherai Beach at around 3.30 p.m. Played there for almost 2-3 hrs, had some bajjis and were back in our hotel by 8 p.m. We were exhausted after washing our salt water soaked clothes. This day, we really had some tough time taking city buses as the destination names were only written in Malayalam. Luckily, as the people there were helpful and most of them were able to speak English, we felt at home. Had roast fish for dinner and went to bed.

8th April, 2008
Had breakfast and were waiting for the taxi to pick us up for local site seeing. Got into the taxi at 9 a.m., reached Aleppey and had a short "backwater boat ride", returned to Kochi at 1 a.m., had lunch and went to boat jetty. There was a boat waiting for us. After boarding, we waited for it to move for almost an hour ;-) Raju and Shashank clicked some pics in the cabin of our boat. We were taken to Mattanchery and Fort Kochi (which are two places on Mattanchery island off the coast of Kochi). Returned to our hotel at 6.30 p.m. (there was a heavy downpour at that time). We (except Vimjam) went to Marine Drive, Kochi to buy some T-shirts and didn't find what we want. So, returned back disappointed. Had dinner at 8 p.m. and went to bed.

9th April, 2008
Woke up early in the morning, had shower and went to Shiva Temple. Had some masala dosas for breakfast and went to hotel to pack our luggage as we need to catch Sabari Express at 11 a.m. Went to railway station, boarded the train, had bread and jam for lunch and reached Coimbatore at 4 p.m. The train reached Salem at 7 p.m and we had biryani for dinner, and as we are more tired in the return journey than we were on the onward journey, went to bed early and woke up when the train is near Ongole station at 5 a.m. As the train was stopped for line clearance, I stepped out of it to pee. It was still dark then and I went few yards away from the train. When I was half done, the train started moving. I really got frightened and got into the train. I'll never forget this incident. Raju informed us that the so-called "foul smell" did come near Singarayakonda station. Since we four of us were asleep at that time, we can't believe his veracity.Had some pooris there for breakfast at Guntur station. Our train reached Secunderabad at 1 p.m. on 10th April and were back to our daily chores sans college.

So, here comes my first ever long trip with my friends. The trip was a huge success: perfectly planned and impeccably executed. All went on perfectly well and the budget too was under Rs.5000/- (smile on everyone's faces). And last, but not the least, five of us were really happy and are eagerly awaiting to go on such trips in the future. It, indeed, is a good experience and will remain as sweet memories of my life. As it was me who planned this tour, it gave lots of confidence....