Finding information about shaders in SFML

[symtaxiz]

Hello World,
I really want to know how to use shaders. I know what shaders are but I don't know how to program it. I would really appreciate if you can tell me where I can find a tutorial to teach me how to use shaders with SFML. But, do the 2d games really need shaders (games with relative good graphics)?
Thanks for answering 

[Jesper Juhl]

You could start by reading the documentation:
  http://www.sfml-dev.org/tutorials/2.1/graphics-shader.php
  http://www.sfml-dev.org/documentation/2.1/classsf_1_1Shader.php

And if you need help with OpenGLSL, have you tried Google?

[symtaxiz]

Thank you! 
I forgot there is a tutorial of SFML   

[eXpl0it3r]

Don't forget the examples: https://github.com/SFML/SFML/tree/master/examples