HALさん:
文書によると「diskutil verify」に対応するみたいですね。
ありゃ、どうも勘違いしているかもしれません。「fy」を「forced repair with all yes」とばかり思っていました。
すると、TS1417の解説が判らなくなってきました;
To use fsck, you must run it from the command line. Unlike using your mouse pointer to open an application to do something, you'll need to type a text command at the prompt (#) to tell fsck what to do. The Terminal application (/Applications/Utilities) and single-user mode are two examples of command-line interfaces in which you can type such commands. To use fsck:
1. Start up your computer in single-user mode to reach the command line.
Note: If necessary, perform a forced restart as described in the Emergency Troubleshooting Handbook that came with your computer. On desktop computers, you can do this by pressing the reset/interrupt button (if there is one) or holding down the power button for several seconds. On portable computers, simultaneously press the Command-Control-power keys. If your portable computer doesn't restart with this method, you may need to reset the Power Manager.
2. At the command-line prompt type:
/sbin/fsck -fy
3. Press Return. fsck will go through five "phases" and then return information about your disk's use and fragmentation. Once it finishes, it'll display this message if no issue is found:
** The volume (name_of_volume) appears to be OK
If fsck found issues and has altered, repaired, or fixed anything, it will display this message:
***** FILE SYSTEM WAS MODIFIED *****
Important: If this message appears, repeat the fsck command you typed in step 2 until fsck tells you that your volume appears to be OK (first-pass repairs may uncover additional issues, so this is a normal thing to do).
4. When fsck reports that your volume is OK, type reboot at the prompt and then press Return.
この「Important:」以下に依れば、「/sbin/fsck -fy」で一度にOKがでない場合でも、何度も繰り返す事でOKがでることがある、と理解していました。
自分は、どこからか間違って理解していた様です。冷静になって見直そうと思います。