Madan Revoor

Emacs – Playing music in your text editor

Madan Revoor — Sun, 20 Dec 2009 07:05:58 +0000

I have always felt it was cool to play music while working on my files. If you are someone like me, I guess you would enjoy this post. I was simply awed when I was introduced to this feature of Emacs for the first time and blown away by the fact that it allows you to play music while working on your files without having to open one of those GUI based players! Imagine it. I felt determined to make it work on my laptop running openSUSE. In this post, we will look at how Emacs can be customized for playing your favorite music without having to switch windows or losing your focus from work!

STEP 1: All you need for Emacs to play music is to download the emms (Emacs Multimedia System) package for Emacs. You can download it from http://www.gnu.org/software/emms/download/emms-3.0.tar.gz

STEP2: Uncompress or extract the archive using the command ‘tar -xvzf emms-3.0.tar.gz’ or you can do it in two steps using ‘gunzip emms-3.0.tar.gz’ and ‘tar -xvf emms-3.0.tar’. After either case, you shall be left with a folder ‘emms-3.0′.

STEP 3: copy the ‘.el’ files to a convenient location like ‘~/elisp/emms’, if you prefer. Or else, you can leave your ‘emms-3.0′ folder under the downloads directory itself if you don’t mind to bother yourself with a bit of organizing data.

STEP 4: We need to add a line to the ‘~/.emacs’ config file to enable it to find the Emms package. Add the following line to it.
(add-to-list ‘load-path “~/elisp/emms/”)

STEP 5: The following lines to be added to the emacs config file to setup emms.
(require ‘emms-setup)
(emms-standard)
(emms-default-players)

STEP 6: The following lines are optional and if added to the config file shall show the currently playing track as a message (like this “Now Playing: /media/music/song/fav.mp3″) in the mini buffer at the bottom of the Emacs editor.

;; Show the current track each time EMMS
;; starts to play a track with “NP : ”
(add-hook ‘emms-player-started-hook ‘emms-show)
(setq emms-show-format “Now Playing : %s”)

STEP 7: This is also an optional step. You can omit it if you do not wish to be shown your own default music directory when prompting emms to play music. Please note that ‘;;’ are comments which need to be removed before replacing your default music directory in the below options. I do not use this option in my setup though.
;; When asked for emms-play-directory,
;; always start from this one
;;(setq emms-source-file-default-directory “/media/sda5/songs/”)
;;(setq emms-source-playlist-default-directory “~/Music/”)

STEP 8: You need to make sure if you have installed the mpg123 audio player. Emms uses mpg123 to play music from within the editor interface and without it, we cannot play music files in our editor. In OpenSUSE 11.2, I installed it using the Yast program. For Ubuntu, you can use the apt-get program.

STEP 9: You are all set to play music in Emacs now! Open up emacs and type ‘M-x emms-add-file’. You shall be asked to type the path of your music directory.
/media/music/songs/fav.mp3

STEP 10: You can start playing the fav.mp3 file by typing ‘M-x emms-start’

STEP 11: You can also enter the interactive emms mode by typing the path of your music directory in STEP 9 instead of pointing it to a single music file. For example, you can type /media/music/songs and then go into interactive mode by typing ‘M-x emms-playlist-mode-go’ and then using the arrow keys to select a track or file to play.

Some of the short cut keys in the interactive playlist mode are listed below:

`n’….Start playing the next track in the playlist.

`p’….Start playing the previous track in the playlist.

`s’….Stop playing.

`f’….Describe the currently playing track in the minibuffer.

`c’….Display the current track in the center of the screen.

`RET’..Start playing the track under point. Note that this is also
available with `‘.

`q’….Put the interactive playlist buffer at the end of the list of all
buffers (ie. bury it).

A few more commands for your emms player:

emms-play-file …………. Play a single file
emms-play-directory …….. Play a whole directory
emms-play-directory-tree … Play a directory tree

Shell script to count number of lines of all files within a directory

Madan Revoor — Sat, 17 Oct 2009 18:02:04 +0000

In this post, I’m going to showcase a small shell script that can count the number of lines in a file and will recursively move through all sub directories and list the count of lines in all files within them. This script helped me during the analysis phase of a project where I had to provide estimates for development based on complexity metrics which was indirectly tied up to the count of lines, the number of files and number of database tables used by each program. This script shall only count the number of lines in a file recursively and display them.

#!/bin/bash

DIR="."	#assigns the current path to this variable

# This function does the work of checking every input
# parameter to test if its a directory or file. If it is a directory
# it recursively calls itself to count the lines of all files within it.
# Else, if it is a file, it invokes 'wc' to print the number of lines in
# that file and stops.

count_lines()
{

if [ ! -d "$1" ]
then
echo "$1"
return
fi
cd "$1"
for file in *
do
if [ -d "$file" ]
then
count_lines "$file"
cd ..
else
count=`wc -l "$file" | cut -d ' ' -f1`
echo "$PWD/$file: $count lines"
fi
done
}

# Main Processing starts here. If no inputs
# offered, run the script on the files in the
# current directory.

if [ $# -eq 0 ]
then
count_lines $DIR	# if no input offered, count_lines of files in current directory
exit 0
fi

# For every input parameter passed to this script,
# count lines of all files within each of them.

for i in $*
do
DIR="$1"
count_lines "$DIR"
shift 1	#Consider the next input parameter
done

Hope you find this script useful. If you have any suggestions, please feel free to offer them. Thanks!

Emacs vs Vi – A single page reference to commands

Madan Revoor — Fri, 11 Sep 2009 18:36:10 +0000

There is nothing new about this post. Emacs and Vi are two of the most powerful editors in the Linux family and I’m no exception in not loving them! I thought it would be a good idea to group both of their commands and keep them on a single page (side-by-side) for a handy reference. I like emacs a little more than Vi as it allows me to listen to music while working on the text (I meant emacs plays music files within the editor interface!). But Vi was the first editor that I learnt to use. I’m equally loyal to both of them. They are both excellent editors and suitable for all of your needs from editing simple text to programming in different languages, whatever they may be. They are my favorites and must be yours too! So, let’s enjoy using them and have some fun!…..

Note: The following list is not exhaustive and only contains those commands which could be identified under both emacs and vi editors. The command descriptions are taken from the emacs reference card and the vi commands were mapped to them. You can download the emacs reference card from here.

Command Description	Emacs	Vi
Read a file	C-x C-f	:r
Save a file to disk	C-x C-s	:w
Insert contents of another file into this buffer	C-x i	:r
Replace this file with the file you really want	C-x C-v	:e
Write buffer to a specified file	C-x C-w	:w
Redraw garbaged screen	C-l	C-l
Regular expression search	C-M-s	/regexp
Reverse regular expression search	C-M-r	?regexp
Move one character backwards	C-b	h
Move one character forwards	C-f	l
Move one word backwards	M-b	b
Move one word forwards	M-f	w
Move cursor up by one line	C-p	j
Move cursor down by one line	C-n	k
Go to line beginning	C-a	^ or 0
Go to line end	C-e	$
Scroll display backward a screen	M-v	C-b
Scroll display forward a screen	C-v	C-f
Scroll current line to center of screen	C-u C-l	C-d or C-u
Delete a character backwards	DEL	x
Delete a character forwards	C-d	x
Delete a word backwards	M-DEL	dw
Delete a word forwards	M-d	dw
Yank back last thing killed	C-y	p
Set mark here	C-@ or C-SPC	ml
Exchange point and mark	C-x C-x	‘l(Goto line with label l)
Interactively replace a text string	M-%	s/a/b/gc
Split window horizontally	C-x 2	C-ws
Delete this window	C-x 0	C-wc
Split window vertically	C-x 3	:vsplit
Indent current line	TAB	<< or >>
Insert newline after point	C-o	O
Join with previous line	M-^	J
Change word to uppercase	M-U	U
Change word to lowercase	M-u	u
Capitalize word	M-c	~ (swap case)

Note: There is a poll embedded within this post, please visit the site to participate in this post's poll.

Mixing JQuery Lightbox with Innerfade – Your own JQuery Slideshow album

Madan Revoor — Fri, 27 Feb 2009 09:38:28 +0000

Did you ever know how simple is it to make a slideshow photo album of your own with JQuery? I tried one by mixing JQuery Lightbox plugin with Innerfade. Some of the best things in life are free and this one’s simple too!

Here goes the code:

Step 1: Download lightbox and innerfade. Place the “jquery.lightbox-0.5.js” and “jquery.innerfade.js” script files into your “js” folder along with other files like “jquery-1.3.1.js”.

Step 2: Copy the CSS stylesheet for lightbox into your ‘css’ folder or in the default theme directory, if you are using WordPress. In WordPress, you shall find the default theme stylesheet, ’style.css’ file at this location.

Step 3: Create the html file for your album. Name it like ‘album.html’. Include the JQuery, lightbox and innerfade script files and any other required stylesheet files as shown below:

Step 4: Create your own script file for the album as ‘album.js’. You must include it in your ‘album.html’ file as shown below:

Step 5: Place the following code into your ‘album.js’ file to set up the JQuery calls that need to be invoked on page load.

$(document).ready(
	function(){
		$('#images').innerfade({
		animationtype: 'slide',  //You can change it to 'fade' to
//create a fade animation in your slideshow
		speed: 750,
		timeout: 2000,
		type: 'sequence',
		containerheight: '75px'
	});

	$('#gallery a').lightBox();
});

The above code defines the options for innerfade like the speed of image swap and animation type. It is important to note that there are two div layers with id=”gallery” and “images”. We apply the lightbox effect to the gallery while invoking the innerfade effect on the images. Don’t worry if its confusing. You will understand it better after we see the next step.

Step 6: Add the following stylesheet code into your default ’style.css’ file. Or you can create your custom ‘gallery.css’ file and link it in the header section of your ‘album.html’ file as follows:

The following code goes into the ‘gallery.css’ file:

#gallery {	}
#gallery ul { list-style: none; }
#gallery ul li { display: inline; }
#gallery ul img {
	border: 0px;
}
#gallery ul a:hover img {
		color: #fff;
}
#gallery ul a:hover { color: #fff; }

Step 7: Add the following final piece of code to the body of your html file (album.html):

The above piece of code creates two div layers. The gallery layer to which the lightbox effect shall be added and the images layer (in fact a ul element) to which the innerfade effect shall be applied to create an impression of a slideshow.

Take care to note where the images are stored. You must refer to the images correctly in the anchor elements.

Thats it! Your own album with slideshow effect is ready! If you click on the slideshow, you can view the images in full size with lightbox effect. Have fun!

Demo: You can try a demo of the slideshow described here.

Adding JQuery to WordPress – For your customized WordPress theme

Madan Revoor — Thu, 26 Feb 2009 14:02:27 +0000

JQuery can be easily added to your WordPress theme. Irrespective of whether you use the default themes from WordPress or if you have customized an unique theme for your website, JQuery will help your website to stand out from the crowd.

I do not prefer to use the integrated WordPress JQuery plugins. In fact, I have not tried them. I always love to add JQuery manually to my WordPress application.

Lets get our hands dirty by straight away jumping into the integration.

Step 1: Create a ‘js’ folder under your WordPress theme directory.

Step 2: Save any of your JQuery stylesheets directly under the theme directory with your other theme stylesheets. One example would be the lightbox stylesheet file.

Step 3: Create a ‘images’ folder under your WordPress theme directory. You may normally already have this directory. Place your JQuery related images under it. For example, the NEXT, PREV and CLOSE buttons of the lightbox plugin can be stored here.

Step 4: create a ‘your_theme_name.js’ file which can be placed under the ‘js’ folder created in step 1.

Sample contents of the js folder:

jquery-1.3.1.js
jquery-lightbox-0.5.js

Step 5: Edit your header.php file in your theme directory to include the ‘your_theme_name.js’ script file and all of your JQuery style sheets (for example the lightbox plugin css file). In this file, you can define the ready() function where JQuery calls can be added.

First, include the script file and stylesheet in your header.php

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