Phil Rousculp asks:
How can I open the user Library folder in a disk image located on an external disk? The technique of selecting Go and holding down the Option key reverts to desktop computer.IDG
You can check your path from a window’s title bar.
Phil is referring to the Go menu in the Finder, which lets you select from a number of folders on the startup drive, including some in your Home directory. In older versions of OS X, selecting the Go menu in the Finder and holding down the Option key toggled showing the Library folder for the currently logged-in user as a choice. In macOS Sierra, the toggle key is now Shift instead of Option.
If you’re trying to find the same directories on drives other than the startup volume, whether they’re internal or external, SSD or hard drive, physical or disk images, you can use the Go > Go To Folder menu item. Apple organizes volumes other than the startup one under the hidden Unix directory /Volumes. So let’s assume the volume name of your mounted disk image is Backup Drive and your Home directory name (the same as your underlying Unix login name) is philr.(The article continues...)