$ gem fetch --help
Usage: gem fetch GEMNAME [GEMNAME ...] [options]
Options:
-v, --version VERSION Specify version of gem to fetch
--platform PLATFORM Specify the platform of gem to fetch
Local/Remote Options:
-B, --bulk-threshold COUNT Threshold for switching to bulk
synchronization (default 1000)
-p, --[no-]http-proxy [URL] Use HTTP proxy for remote operations
--source URL Use URL as the remote source for gems
Common Options:
-h, --help Get help on this command
-V, --[no-]verbose Set the verbose level of output
-q, --quiet Silence commands
--config-file FILE Use this config file instead of default
--backtrace Show stack backtrace on errors
--debug Turn on Ruby debugging
Arguments:
GEMNAME name of gem to download
Summary:
Download a gem and place it in the current directory
Defaults:
--version '>= 0'
Вы должны быть в состоянии сделать
$ gem fetch gosu --platform x86-mswin32
Или просто перейдите на страницу загрузки .