Installing Cygwin packages from the command-line [duplicate]

Possible Duplicate:
upgrading and installing packages through the cygwin command line?

I'm looking for a "yum"-link method to install additional Cygwin packages from the command-line. Let's say I want to add the package "Math/bc", then ideally I'd like to be able to do it using one command as in:

yum install bc

Currently the only way I've found to install new packages is to locate and run the installation file SETUP.EXE file and then scroll to the relevant package, add it, etc. This is quite cumbersome so I'm sure there is a smarter command-line way to add an additional package.

lynx -source rawgit.com/transcode-open/apt-cyg/master/apt-cyg > apt-cyg
install apt-cyg /bin
apt-cyg install bc