Changing Vim indentation behavior by file type

Put autocmd commands based on the file suffix in your ~/.vimrc

autocmd BufRead,BufNewFile   *.c,*.h,*.java set noic cin noexpandtab
autocmd BufRead,BufNewFile   *.pl syntax on

The commands you're looking for are probably ts= and sw=

Use ftplugins or autocommands to set options.

ftplugin

In ~/.vim/ftplugin/python.vim:

setlocal shiftwidth=2 softtabstop=2 expandtab

And don't forget to turn them on in ~/.vimrc:

filetype plugin indent on

(:h ftplugin for more information)

autocommand

In ~/.vimrc:

autocmd FileType python setlocal shiftwidth=2 softtabstop=2 expandtab

I would also suggest learning the difference between tabstop and softtabstop. A lot of people don't know about softtabstop.

edit your ~/.vimrc, and add different file types for different indents,e.g. I want html/rb indent for 2 spaces, and js/coffee files indent for 4 spaces:

" by default, the indent is 2 spaces. 
set shiftwidth=2
set softtabstop=2
set tabstop=2

" for html/rb files, 2 spaces
autocmd Filetype html setlocal ts=2 sw=2 expandtab
autocmd Filetype ruby setlocal ts=2 sw=2 expandtab

" for js/coffee/jade files, 4 spaces
autocmd Filetype javascript setlocal ts=4 sw=4 sts=0 expandtab
autocmd Filetype coffeescript setlocal ts=4 sw=4 sts=0 expandtab
autocmd Filetype jade setlocal ts=4 sw=4 sts=0 expandtab

refer to: Setting Vim whitespace preferences by filetype

You can add .vim files to be executed whenever vim switches to a particular filetype.

For example, I have a file ~/.vim/after/ftplugin/html.vim with this contents:

setlocal shiftwidth=2
setlocal tabstop=2

Which causes vim to use tabs with a width of 2 characters for indenting (the noexpandtab option is set globally elsewhere in my configuration).

This is described here: http://vimdoc.sourceforge.net/htmldoc/usr_05.html#05.4, scroll down to the section on filetype plugins.