It seems so straightforward: I get an external HD, copy the internal to it, wipe the internal, reinstall the original system software, then copy back my personal directory (and whatever else I find I need) from the external.
(The reason for all this is that some change in the past year has impaired my Mac’s ability to play sound, and I’d like to at least find out which change it was. Also, Cyrillic doesn’t display since I went crazy and installed my old font collection.)
If I drag the “Macintosh HD” icon to the “External” icon, Finder creates an alias rather than a copy. If I open the Macintosh HD and drag all the top-level folders, Finder objects because I, as a plain user, lack permission for some of the files. (Is there a way to run Finder as superuser?) Disk Utility won’t make a disk image of Macintosh HD: “Resource busy,” presumably because it is the startup disk.
So I run cp -Rp and come back eight hours later to find that the target disk is full, presumably because of a loop: /Volumes/Macintosh HD/Volumes/ contains both Macintosh HD and External. (The GNU version of cp has an option cp -x to ignore subdirectories on other filesystems, but MacBSD’s cp lacks that.) I guess I’ll use a shellscript that enumerates the top directories (except Volumes) explicitly.
I probably won’t need to save anything other than Users, Applications and Library — and life would be simpler if I could be sure of that.
next day: Okay, the script apparently worked, until it came to the folder Applications (Mac OS 9) — I had forgotten that the shell would be unhappy about the parenthesis. But now the external disc (which is on USB) has unmounted itself.
later same day: Well, it’s all done now. iTunes still won’t make noises, but now (after updating Quicktime) I can hear YouTube for a change.