Style

Many style guides are available. These describe best practices and “correct” ways to do things such as indentation, variable naming, etc. Such things are not usually part of the language specification, but nevertheless are critical to the maintainability of a project’s code base.

General

• https://github.com/styleguide/ (ruby, android, CSS)
• https://code.google.com/p/google-styleguide/ (many languages)
• https://github.com/necolas/idiomatic-css

Language Centric

Perl

• (official) http://perldoc.perl.org/perlstyle.html

Ruby

• (unofficial) https://github.com/styleguide/ruby

Python

• PEP8 https://www.python.org/dev/peps/pep-0008/
• Google https://google-styleguide.googlecode.com/svn/trunk/pyguide.html
• Python-guide: http://docs.python-guide.org/en/latest/writing/style/

Java

• Google https://google-styleguide.googlecode.com/svn/trunk/javaguide.html
• Android https://source.android.com/source/code-style.html