The default MacPorts installation downloads each dependency, builds and installs it, then downloads, builds and installs the next dependency, and so on. This means that a constant network connection is required throughout the installation. In my configuration, a constant network connection is not feasible. This means that installation of a large-dependency package can take a very long time.
How do I download all dependencies for a specified MacPorts package at the beginning (while connected to the network) and then build and install each dependency (no network connection required)?
While connected to the network, use:
port fetch rdepof:<packagename> <packagename>
Then, with no network connection required, use:
port clean rdepof:<packagename> <packagename>
port install <packagename>
rdepof: is a recursive list of all of the package's dependencies. The clean command removes any previous builds of the package or its dependencies.
Use port fetch <packagename>.
来源：https://stackoverflow.com/questions/4755274/downloading-macports-dependencies-without-installing