Best Known Method

Markdown

Online Editor

• StackEdit - Extended markdown support on LaTeX mathematical expressions and UML diagrams
• Math Online Editor - Writing math texts for the web with LaTeX equations support

Table of Content

<link rel="stylesheet" href="http://yandex.st/highlightjs/6.2/styles/googlecode.min.css">
  
<script src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
<script src="http://yandex.st/highlightjs/6.2/highlight.min.js"></script>
  
<script>hljs.initHighlightingOnLoad();</script>
<script type="text/javascript">
 $(document).ready(function(){
      $("h2,h3,h4,h5,h6").each(function(i,item){
        var tag = $(item).get(0).localName;
        $(item).attr("id","wow"+i);
        $("#category").append('<a class="new'+tag+'" href="#wow'+i+'">'+$(this).text()+'</a></br>');
        $(".newh2").css("margin-left",0);
        $(".newh3").css("margin-left",20);
        $(".newh4").css("margin-left",40);
        $(".newh5").css("margin-left",60);
        $(".newh6").css("margin-left",80);
      });
 });
</script>
<div id="category"></div>

Page Break

<div style="page-break-after: always;"></div>

Image in Width/Height

<center>
<img src="images/drawing.png" alt="Drawing" style="width: 600px;"/>
</center>

Centering an Image

<p align="center">
  <img src="https://assets-cdn.github.com/images/modules/logos_page/GitHub-Mark.png" width="256" title="Github Logo">
</p>

-or-

<center>![](image.png)

Text in Color

<span style="color:red">Text in red color</span>

Gravizo - Graphviz, UMLGraph or PlantUML in Markdown

A simple way of describing graphs and include it easily in your web for free, blog, markdown page, github, and any location where remote images can be showed.

Gravizo uses Graphviz to render graphs. It supports DOT, PlantUML, UMLGraph syntax and SVG in JSON format. It will include other formats in the future. No javascript, no plugins needed so you can include in any document.

Example:

![Alt text](http://g.gravizo.com/g? digraph G { aize ="4,4"; main [shape=box]; main -> parse [weight=8]; parse -> execute; main -> init [style=dotted]; main -> cleanup; execute -> { make_string; printf}; init -> make_string; edge [color=red]; main -> printf [style=bold,label="100 times"]; make_string [label="make a string"]; node [shape=box,style=filled,color=".7 .3 1.0"]; execute -> compare; } )

![Alt text](http://g.gravizo.com/g?
digraph G {
aize ="4,4";
main [shape=box];
main -> parse [weight=8];
parse -> execute;
main -> init [style=dotted];
main -> cleanup;
execute -> { make_string; printf};
init -> make_string;
edge [color=red];
main -> printf [style=bold,label="100 times"];
make_string [label="make a string"];
node [shape=box,style=filled,color=".7 .3 1.0"];
execute -> compare;
}
)

![Alt text](http://g.gravizo.com/g? @startuml; actor User; participant "First Class" as A; participant "Second Class" as B; participant "Last Class" as C; User -> A: DoWork; activate A; A -> B: Create Request; activate B; B -> C: DoWork; activate C; C --> B: WorkDone; destroy C; B --> A: Request Created; deactivate B; A --> User: Done; deactivate A; @enduml )

![Alt text](http://g.gravizo.com/g?
@startuml;
actor User;
participant "First Class" as A;
participant "Second Class" as B;
participant "Last Class" as C;
User -> A: DoWork;
activate A;
A -> B: Create Request;
activate B;
B -> C: DoWork;
activate C;
C --> B: WorkDone;
destroy C;
B --> A: Request Created;
deactivate B;
A --> User: Done;
deactivate A;
@enduml
)

http://www.gravizo.com

https://github.com/TLmaK0/gravizo

Support LaTeX Math

Rendering with MathJax

<style TYPE="text/css">
code.has-jax {font: inherit; font-size: 100%; background: inherit; border: inherit;}
</style>
<script type="text/x-mathjax-config">
MathJax.Hub.Config({
    tex2jax: {
        inlineMath: [['$','$'], ['\\(','\\)']],
        skipTags: ['script', 'noscript', 'style', 'textarea', 'pre'] // removed 'code' entry
    }
});
MathJax.Hub.Queue(function() {
    var all = MathJax.Hub.getAllJax(), i;
    for(i = 0; i < all.length; i += 1) {
        all[i].SourceElement().parentNode.className += ' has-jax';
    }
});
</script>
<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>

And then:

`$x^2$` or `$$x^2$$`

Example:

`$$f(x) = \sin (x^2 + y^2) + {1 \over x + y}$$`

`$$
\begin{align*}
  & \phi(x,y) = \phi \left(\sum_{i=1}^n x_ie_i, \sum_{j=1}^n y_je_j \right)
  = \sum_{i=1}^n \sum_{j=1}^n x_i y_j \phi(e_i, e_j) = \\
  & (x_1, \ldots, x_n) \left( \begin{array}{ccc}
      \phi(e_1, e_1) & \cdots & \phi(e_1, e_n) \\
      \vdots & \ddots & \vdots \\
      \phi(e_n, e_1) & \cdots & \phi(e_n, e_n)
    \end{array} \right)
  \left( \begin{array}{c}
      y_1 \\
      \vdots \\
      y_n
    \end{array} \right)
\end{align*}
$$`

http://stackoverflow.com/questions/2188884/how-can-i-mix-latex-in-with-markdown

github/markup#274

http://meta.math.stackexchange.com/questions/5020/mathjax-basic-tutorial-and-quick-reference

CodeCogs Equation Editor

<img src="http://latex.codecogs.com/gif.latex?\frac{\partial J}{\partial \theta_k^{(j)}}=\sum_{i:r(i,j)=1}{\big((\theta^{(j)})^Tx^{(i)}-y^{(i,j)}\big)x_k^{(i)}}+\lambda \theta_k^{(j)}" />

![](http://latex.codecogs.com/gif.latex?\\frac{\\partial J}{\\partial \\theta_k^{(j)}}=\\sum_{i:r(i,j)=1}{\\big((\\theta^{(j)})^Tx^{(i)}-y^{(i,j)}\\big)x_k^{(i)}}+\\lambda \\theta_k^{(j)})

}}=\sum_{i:r(i,j)=1}{\big((\theta^{(j)})^Tx^{(i)}-y^{(i,j)}\big)x_k^{(i)}}+\lambda \theta_k^{(j)})

![](http://latex.codecogs.com/gif.latex?\\frac{1}{1+sin(x)})

注意要双反斜线\\来escape

https://www.zhihu.com/question/26887527

http://latex.codecogs.com/

TeX / LaTeX

# compile
latex foo.tex
# display on screen with X11
xdvi foo.dvi
# convert dvi to postscript
dvips -Pcmz foo.dvi foo.ps
# convert dvi to pdf
dvipdf foo.dvi

Git / GitHub

Starts

To get a list of users that have stared a repository you can append /stargazers to the url of the repository:

https://github.com/[user]/[repo]/stargazers

Watchers

You can also see who the watchers:

https://github.com/[user]/[repo]/watchers

http://webapps.stackexchange.com/questions/41799/how-can-i-list-people-who-have-starred-my-github-repository

Trending

Trending in open source: https://github.com/trending

Hot Projects

Most forks: https://github.com/search?o=desc&q=stars:%3E1&s=forks&type=Repositories

Most stars: https://github.com/search?q=stars:%3E1&s=stars&type=Repositories

http://stackoverflow.com/questions/19855552/how-to-find-out-the-most-popular-repositories-on-github

Import CVS Repositories

sudo apt-get install git-cvs
git cvsimport -v -d :pserver:anonymous@basicsynth.cvs.sourceforge.net:/cvsroot/basicsynth Src

https://pkp.sfu.ca/wiki/index.php/HOW-TO_import_and_export_to_and_from_Git_and_CVS

http://www.gromacs.org/Developer_Zone/Git/Migrating_a_CVS_repository_to_GIT

https://git-scm.com/docs/git-cvsimport

http://cvs2svn.tigris.org/cvs2git.html

http://stackoverflow.com/questions/881158/is-there-a-migration-tool-from-cvs-to-git

http://stackoverflow.com/questions/11362676/how-to-import-and-keep-updated-a-cvs-repository-in-git

git cvsimport -v -d :pserver:anonymous@cvs.drupal.org:/cvs/drupal-contrib contributions/modules/module-name

This would login to cvs.drupal.org using the CVS's pserver login method, provide the username anonymous and the password (for anonymous access, the password is almost always anonymous), set the CVS document root to /cvs/drupal-contrib, and pull the code located at contributions/modules/module-name into the current working directory as a git repository.

https://maymay.net/blog/2008/04/15/how-to-import-cvs-code-repositories-into-git-using-git-cvsimport/

Shell

Batch Renaming

Rename '.png.jpg' to '.jpg':

rename '.png.jpg' '.jpg' ./*

-or-

cd dir/with/messedup/files

for file in *.png.jpg; do
	mv "$file" "${file%.png.jpg}.jpg"
done

-or-

for fn in *.jpg; do convert "$fn" `echo $fn | sed 's/jpg$/png/'`; done

-or-

ls *.jpg | xargs -I{} convert "{}" `echo {} | sed 's/jpg$/png/'`

This can be also be done with xargs and sed to change the file extension:

ls | grep \.png$ | sed 'p;s/\.png/\.jpg/' | xargs -n2 mv

-or-

find . -name "*.png" -print0 | sed 'p;s/\.png/\.jpg/' | xargs -0 -n2 mv

-or-

ls *.svg.png | xargs basename -s .svg.png | xargs -I {} mv {}.svg.png {}.png

If you have files in subdirectories that you want converted, then you can pipe find to a while read loop:

find . -type f -name '*.png' |
while read file; do
	convert "$file" -resize "${file%.png}.jpg"
done

http://stackoverflow.com/questions/10972002/batch-renaming-files-in-command-line-and-xargs

Random File

Choose a random file from a directory in a shell script:

ls path/to/*.mp3 | awk 'BEGIN{ srand(); } { line[NR]=$0 } END{ print line[(int(rand()*NR+1))] }'

echo `find . -maxdepth 1 -mindepth 1 -type f -print0 | sort --zero-terminated --random-sort |  sed 's/\d000.*//g'`

find . -type f | shuf -n1

for f in `ls /usr/bin`; do  echo "$RANDOM $f" ; done | sort -R | head -n1 | cut -d' ' -f2-

http://stackoverflow.com/questions/701505/best-way-to-choose-a-random-file-from-a-directory-in-a-shell-script

pv

Simulate typing:

echo "You can simulate on-screen typing just like in the movies" | pv -qL 10

Monitor progress of a command:

pv access.log | gzip > access.log.gz

Live ssh network throughput test:

yes | pv | ssh $host "cat > /dev/null"

pv /dev/zero|ssh $host 'cat > /dev/null'

Time how fast the computer reads from /dev/zero:

pv /dev/zero > /dev/null

Copy a file using pv and watch its progress:

pv sourcefile > destfile

https://blog.urfix.com/9-tricks-pv-pipe-viewer/

Transfer a directory from A to B and monitor progress:

# on computer A, with IP address 192.168.1.100
$ tar -cf - /path/to/dir | pv | nc -l -p 6666 -q 5
# on computer B
$ nc 192.168.1.100 6666 | pv | tar -xf -

http://www.catonmat.net/blog/unix-utilities-pipe-viewer/

Using pv and dialog together to create a dialog progress:

tar -czf - ./Documents/ | (pv -n > backup.tgz) 2>&1 | dialog --gauge "Progress" 10 70

http://www.tecmint.com/monitor-copy-backup-tar-progress-in-linux-using-pv-command/

Extract tar ball and show progress using the dialog command:

(pv -n backup.tar.gz | tar xzf - -C path/to/data ) 2>&1 | dialog --gauge "Running tar, please wait..." 10 70 0

http://www.cyberciti.biz/open-source/command-line-hacks/pv-command-examples/

SSH

Piping the microphone from one machine to the speakers of another:

dd if=/dev/dsp | ssh -C user@host dd of=/dev/dsp

-or-

dd if=/dev/dsp | ssh -c arcfour -C user@host dd of=/dev/dsp

Tunnel audio chat over ssh:

arecord -f cd -t raw | oggenc - -r | ssh user@host mplayer -

Audio

Wav -> MP3

ffmpeg -i input.wav -vn -ar 44100 -ac 2 -ab 192k -f mp3 output.mp3

ffmpeg -i audio.wav -acodec libmp3lame audio.mp3

http://stackoverflow.com/questions/3255674/convert-audio-files-to-mp3-using-ffmpeg

http://www.catswhocode.com/blog/19-ffmpeg-commands-for-all-needs

Convert a video into animated GIF

ffmpeg -i video.mp4 -vf scale=500:-1 -t 10 -r 10 image.gif

http://www.labnol.org/internet/useful-ffmpeg-commands/28490/

http://www.tecmint.com/ffmpeg-commands-for-video-audio-and-image-conversion-in-linux/

Imaging

Image conversion:

convert icon.svg -scale 32 tmp/32.png
convert tmp/16.png tmp/32.png tmp/48.png tmp/128.png tmp/256.png  icon.ico

/usr/bin/convert -resize x16 -gravity center -crop 16x16+0+0 input.jpg \
-transparent white -colors 256 output/favicon.ico

/usr/bin/convert -resize x16 -gravity center -crop 16x16+0+0 input.png \
-flatten -colors 256 output/favicon.ico

ffmpeg -i img.png img.ico
ffmpeg -i input.jpg -vf scale=320:240 output_320x240.png
ffmpeg -i input.jpg -vf scale=320:-1 output_320.png

https://trac.ffmpeg.org/wiki/Scaling%20(resizing)%20with%20ffmpeg

Web Development

JavaScript Compressor

YUI Compressor

Google Closure Compiler

Dojo ToolKit's ShrinkSafe compiler

JSMin

UglifyJS

http://stackoverflow.com/questions/599911/what-do-you-use-to-minimize-and-compress-javascript-libraries

http://stackoverflow.com/questions/28932/best-javascript-compressor

Tool to Unminify / Decompress JavaScript

• JSBeautifier
• Javascript Formatter
• UNMINIFY - Unminify JS, CSS and HTML Code

http://stackoverflow.com/questions/822119/tool-to-unminify-decompress-javascript

Start a Web Server in Any Folder

Python

$ python -m SimpleHTTPServer 8080

Replace 8080 with another number if you want it to listen on a different port.

For ports < 1024 it needs to run with root privileges.

The python 3.x equivalent of this is:

$ python3 -m http.server

PHP

$ php -S 0.0.0.0:8080

Ruby

Without gem

$ ruby -run -e httpd . -p8080

With serve

$ gem install serve
$ serve 8080

Node.js

Use Connect and ServeStatic with Node.js:

1. Install connect and serve-static with NPM

   $ npm install connect serve-static

2. Create server.js file with this content:

   var connect = require('connect');
   var serveStatic = require('serve-static');
   connect().use(serveStatic(__dirname)).listen(8080, function(){
       console.log('Server running on 8080...');
   });

3. Run with Node.js

   $ node server.js

Simplest Node.js server:

$ npm install http-server -g
$ http-server

Reference