⚠️ This is an old post.

Content may be out of date.

The createinstallmedia utility can be used to create a bootable macOS installation disk, which is useful for installing macOS on multiple Macs without downloading the installer over the Internet each time:

/path/to/macOS/installer.app/Contents/Resources/createinstallmedia --volume /path/to/installation/media/volume --applicationpath /path/to/macOS/installer.app --nointeraction

For example, to use an external drive named myDrive to create an installation disk for macOS High Sierra the following command can be used:

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/myDrive --applicationpath /Applications/Install\ macOS\ High\ Sierra.app --nointeraction

Gist on GitHub