These files are sample configuration files.
Useally, you don't need this, but when you want to ...

  1. Execute your favorite command
     If you want to execute some command at start sesssion.
     use [hook] file

  2. Set XIM host
     Normally, XIM connects some servers to convert characters.
     If you want to use your-specified host, use [im_host] file

  3. Customize Environment
     If you want to export some Environments, use [custom] file


Each file should place to $HOME/.xinit.d/

Have fun ;-)
