问题
When writing executable scripts, and declarative configuration files that use a common language (eg. Python), I often find it undesirable to add an extension to the file name. Many syntax-highlighting text editor (eg. Geany) are subsequently unable to automatically determine the filetype.
Is there any standard method for indicating to editors the type of source in the file?
回答1:
Typically the shebang line is used as a fall-back.
For example, a Ruby script without an extension would begin with:
#!/usr/bin/env ruby
回答2:
Vim
Vim has a concept called a modeline. A modeline is a specially formatted line either withinin the first or last 5 lines of the textfile, which allows you to :setlocal local variables. For example, for C:
/* vi: set filetype=c fileencoding=UTF-8 shiftwidth=4 tabstop=4 expandtab */
or Ruby:
# vi: set filetype=ruby fileencoding=UTF-8 shiftwidth=2 tabstop=2 expandtab
Some more documentation.
Emacs
Emacs has a similar concept, called File Variables.
File Variables are either specified at the beginning of the file (in the first line, or if there is a shebang line, then in the second) in this form:
/* *-* mode: cc c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil *-* */
or at the end:
# Local Variables:
# mode: ruby
# coding: utf-8
# c-basic-offset: 2
# tab-width: 2
# indent-tabs-mode: nil
# End:
jEdit
jEdit calls this buffer-local properties. The have to sit within the first or last 10 lines and look like this:
# :mode=ruby:indentSize=2:tabSize=2:noTabs=true:
jEdit also uses the shebang line as a fallback for mode detection.
Komodo Edit
There is a plugin called Komode (pun intended) which adds modeline support to Komodo Edit:
# komode: le=unix language=ruby codepage=utf8 tab=2 notabs indent=2
It also understands a limited subset of Vim modelines.
Others
A lot of other editors also have either their own variants of this, or support one of the above (usually Vim).
Python / Ruby encoding
Both Ruby 1.9 and Python require that the encoding for non-ASCII source files be explicitly specified. Fortunately, they do this in a way that is compatible with both Emacs and Vim modelines. (Basically, they look for the string coding followed by a non-word character followed by whitespace followed by a valid encoding name. Both Vim's fileencoding= and Emacs' coding: satisfy these requirements.)
Modeline Generator
Here is a simple modeline generator, which generates modelines for Vim, Emacs and jEdit.
回答3:
This works for many editors if you're using non-standard shebangs:
#!/usr/bin/env python3
# filetype=python
来源：https://stackoverflow.com/questions/1984072/indicate-programming-language-in-a-file-without-extension