fsdb_hfs.1m (2010 09)

ManualsBrandsHP ManualsSoftwareHP-UX Manpages

fsdb_hfs(1M) fsdb_hfs(1M)

NAME

fsdb_hfs: fsdb - HFS ﬁle system debugger

SYNOPSIS

/usr/sbin/fsdb

[-F hfs][-V] special [

-b blocknum][-]

Remarks

Always execute the

fsck command (see fsck (1M)) after running

fsdb.

DESCRIPTION

The

fsdb command can be used to patch up a damaged ﬁle system after a crash.

Options and Arguments

fsdb recognizes the following options and arguments.

special The ﬁle name of the special ﬁle containing the ﬁle system.

- Initially disable the error-checking routines that are used to verify the inode and

fragment addresses. See the O symbol. If used, this option must follow special on

the command line.

-b blocknum Use blocknum as the superblock for the ﬁle system. If used, this option must follow

special on the command line.

-F hfs Specify the HFS ﬁle system type.

-V Echo the completed command line, but perform no other action. The command line

is generated by incorporating the user-speciﬁed options and other information

derived from the /etc/fstab ﬁle. This option allows the user to verify the com-

mand line.

Operation

fsdb normally uses the ﬁrst superblock for the ﬁle system, located at the beginning of the disk section,

as the effective superblock. An alternate superblock can always be found at block

((SBSIZE+BBSIZE)/DEV_BSIZE)

, typically block 16. The -b option can be used to specify the

superblock location.

fsdb deals with the ﬁle system in terms of block fragments, which are the unit of addressing in the ﬁle

system and the minimum unit of space allocation. To avoid possible confusion, fragment is used to mean

that, and block is reserved for the larger true block. fsdb has conversions to translate fragment

numbers and i-numbers into their corresponding disk addresses. Also included are mnemonic offsets to

access different parts of an inode. These greatly simplify the process of correcting control block entries or

descending the ﬁle system tree.

fsdb contains several error-checking routines to verify inode and fragment addresses. These can be dis-

abled if necessary by invoking fsdb with the optional - argument, or by using the O symbol.

Numbers are considered decimal by default. Octal numbers must be preﬁxed with a zero. Hexadecimal

numbers must be preﬁxed with

0x. During any assignment operation, numbers are checked for a possi-

ble truncation error due to a size mismatch between source and destination.

fsdb reads a fragment at a time. A buffer management routine is used to retain commonly used frag-

ments of data in order to reduce the number of read system calls. All assignment operations result in an

immediate write-through of the corresponding fragment.

Symbols

The following symbols are recognized by

fsdb:

! Escape to shell

# Absolute address

+ Address arithmetic

- Address arithmetic

< Restore an address

> Save an address

= Numerical assignment

=+ Incremental assignment

=- Decremental assignment

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (4 pages)

PAGE 1
fsdb_hfs(1M) fsdb_hfs(1M) NAME fsdb_hfs: fsdb - HFS file system debugger SYNOPSIS /usr/sbin/fsdb [-F hfs] [-V] special [-b blocknum ] [-] Remarks Always execute the fsck command (see fsck (1M)) after running fsdb. DESCRIPTION The fsdb command can be used to patch up a damaged file system after a crash. Options and Arguments fsdb recognizes the following options and arguments. special The file name of the special file containing the file system.
PAGE 2
fsdb_hfs(1M) =" b d f i p q B D O W X A fsdb_hfs(1M) Character string assignment Convert from fragment number to disk address (historically "block") Directory slot offset File print facility Convert from i-number to inode address; for continuation inodes as well as primary inodes General print facility Quit Byte mode Double-word mode Error checking flip-flop Word mode Hexadecimal flip-flop Dots, tabs, and spaces can be used as function delimiters, but are not necessary.
PAGE 3
fsdb_hfs(1M) maj md min mt sz uid fsdb_hfs(1M) Major device number Mode Minor device number Time last modified File size in byte unit User ID number The following mnemonics are used for directory examination: di nm I-number of the associated directory entry Name of the associated directory entry EXAMPLES 386i Print i-number 386 in an inode format. This now becomes the current working inode. ln=4 Change the link count for the working inode to 4. ln=+1 Increment the link count by 1.
PAGE 4
(Notes) A (Notes) fA 4 Hewlett-Packard Company −1− HP-UX 11i Version 3: September 2010