I want to recommend lice to any developer using common licenses such as the GPL or BSD-3 or MIT. Lice is a command-line program which can generate these licenses for you, allowing you to specify (where necessary) variables such as the year or your organization or company name. It can also output a license wrapped in comments for a variety of programming languages, e.g.
lice --language lua gpl3 prints out a copy of the GPLv3 wrapped in a comment block for Lua.
Next time you start to copy-paste a license from one project or one source file to another, stop and check out lice instead.