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From: scott@soda.berkeley.edu (Scott Silvey)
Newsgroups: comp.unix.wizards,comp.unix.questions,comp.unix.bsd
Subject: BSD filesystem and od utility
Date: 22 Jul 1993 21:51:05 GMT
Organization: U.C. Berkeley, CS Undergraduate Association
Lines: 54
Distribution: world
Message-ID: <22n249$2fv@agate.berkeley.edu>
NNTP-Posting-Host: soda.berkeley.edu
Hello all!
For those of you out there who are familiar with the 'od'
utility and directory content of a BSD filesystem, I have
a few questions for you. Please note that the data below
was produced on a BSD 4.3 machine.
When I use "od -cdw12 ~" I get the following (which is, of
course, not the complete listing)
0000000 \0 \0 016 \0 \0 \f \0 001 . \0 \0 \0
00000 03584 00012 00001 11776 00000
0000014 \0 \0 007 \0 \0 \f \0 002 . . \0 \0
00000 01792 00012 00002 11822 00000
0000030 \0 \0 016 001 \0 024 \0 013 . X r e
00000 03585 00020 00011 11864 29285
0000044 s o u r c e s \0 \0 \0 016 002
29551 30066 25445 29440 00000 03586
0000060 \0 020 \0 006 . a l i a s \0 \0
00016 00006 11873 27753 24947 00000
0000074 \0 \0 016 003 \0 020 \0 006 . c s h
00000 03587 00016 00006 11875 29544
0000110 r c \0 \0 \0 \0 016 004 \0 020 \0 004
29283 00000 00000 03588 00016 00004
0000124 . e n v \0 \0 \0 \0 \0 \0 016 005
11877 28278 00000 00000 00000 03589
My questions are as follows:
1) [looking at the row starting at offset 0]: what does the '016'
entry mean? This entry is also found as a delimeter in the
other file entries as well. I have also observed that different
users on a system usually have a different delimeter than
'016' (I have also seen 'M', 'T', '020', etc... used). Why/What
is this?
I realize that '3584' is an inode entry and '001' is a file
length, but what is the '11776' entry in the second row?
2) Why is the data in the second row of each offset put into
groups of 5 bytes each? These groupings also appear to have
a correlation to the data of line 1 of each offset (a form
feed '\f', is indeed an ascii '012'), but what is it?
Any information would be greatly appreciated.
Thanx in advance,
Jon.
P.S. Please mail replies/clarifications to 'jon@lurnix.com' - I don't
get to read news very often and this will insure I get your reply.