Is there a command that tells you the other gems that a gem depends on?
Also, is there a way to auto install the gem's dependencies?
The following information was pulled from the rubygems command reference linked below.
http://guides.rubygems.org/command-reference/#gem-dependency
The first command you're asking for is "gem dependency". Below is the command description.
gem dependency GEMNAME [options]
Options:
-v, --version VERSION Specify version of gem to dependency
-r, --[no-]reverse-dependencies Include reverse dependencies in the output
-p, --pipe Pipe Format (name --version ver)
Common Options:
--source URL Use URL as the remote source for gems
-h, --help Get help on this command
--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 gems to show
Summary:
Show the dependencies of an installed gem
Defaults:
--version '> 0' --no-reverse
The second command you'll need is "gem install". Dependencies get installed automatically. Read the quote below from the command reference for more detail.
"gem install" will install the named gem. It will attempt a local installation (i.e. a .gem file in the current directory), and if that fails, it will attempt to download and install the most recent version of the gem you want.
If a gem is being installed remotely, and it depends on other gems that are not installed, then gem will download and install those, after you have confirmed the operation.