.\" -*- nroff -*-
.\" Copyright 1993, 1994, 1995 by Theodore Ts'o. All Rights Reserved.
.\" This file may be copied under the terms of the GNU Public License.
-.\"
+.\"
.TH DEBUGFS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
.SH NAME
debugfs \- ext2/ext3/ext4 file system debugger
superblock
]
[
-.B \-f
+.B \-f
cmd_file
]
[
device
]
.SH DESCRIPTION
-The
-.B debugfs
+The
+.B debugfs
program is an interactive file system debugger. It can be used to
examine and change the state of an ext2, ext3, or ext4 file system.
.br
catastrophic mode forces the filesystem to be opened read-only.
.TP
.I \-i
-Specifies that
+Specifies that
.I device
represents an ext2 image file created by the
.B e2image
program. Since the ext2 image file only contains the superblock, block
-group descriptor, block and inode allocation bitmaps, and
+group descriptor, block and inode allocation bitmaps, and
the inode table, many
.B debugfs
-commands will not function properly.
+commands will not function properly.
.B Warning:
-no safety checks are in place, and
-.B debugfs
+no safety checks are in place, and
+.B debugfs
may fail in interesting ways if commands such as
-.IR ls ", " dump ", "
-etc. are tried without specifying the
+.IR ls ", " dump ", "
+etc. are tried without specifying the
.I data_source_device
-using the
+using the
.I \-d
option.
-.B debugfs
+.B debugfs
is a debugging tool. It has rough edges!
.TP
.I -d data_source_device
-Used with the
+Used with the
.I \-i
option, specifies that
.I data_source_device
option.
.TP
.I -f cmd_file
-Causes
+Causes
.B debugfs
-to read in commands from
-.IR cmd_file ,
-and execute them. When
+to read in commands from
+.IR cmd_file ,
+and execute them. When
.B debugfs
is finished executing those commands, it will exit.
.TP
not support Direct I/O.
.TP
.I -R request
-Causes
+Causes
.B debugfs
-to execute the single command
+to execute the single command
.IR request ,
and then exit.
.TP
.I -V
-print the version number of
+print the version number of
.B debugfs
and exit.
.SH SPECIFYING FILES
.B debugfs
commands take a
.I filespec
-as an argument to specify an inode (as opposed to a pathname)
-in the filesystem which is currently opened by
-.BR debugfs .
+as an argument to specify an inode (as opposed to a pathname)
+in the filesystem which is currently opened by
+.BR debugfs .
The
.I filespec
-argument may be specified in two forms. The first form is an inode
-number surrounded by angle brackets, e.g.,
+argument may be specified in two forms. The first form is an inode
+number surrounded by angle brackets, e.g.,
.IR <2> .
The second form is a pathname; if the pathname is prefixed by a forward slash
-('/'), then it is interpreted relative to the root of the filesystem
-which is currently opened by
+('/'), then it is interpreted relative to the root of the filesystem
+which is currently opened by
+.BR debugfs .
+If not, the pathname is
+interpreted relative to the current working directory as maintained by
.BR debugfs .
-If not, the pathname is
-interpreted relative to the current working directory as maintained by
-.BR debugfs .
-This may be modified by using the
+This may be modified by using the
.B debugfs
command
.IR cd .
-.\"
+.\"
.\"
.\"
.SH COMMANDS
-This is a list of the commands which
+This is a list of the commands which
.B debugfs
supports.
.TP
-.I blocks filespace
+.BI blocks " filespace"
Print the blocks used by the inode
.I filespec
to stdout.
.TP
-.I bmap filespec logical_block
+.BI bmap " filespec logical_block"
Print the physical block number corresponding to the logical block number
.I logical_block
in the inode
.IR filespec .
.TP
-.I block_dump [-f out_file] block_num
-Dump the contents of a block, optionally to
-.IR out_file .
+.BI block_dump " [-f filespec] block_num"
+Dump the filesystem block given by
+.I block_num
+in hex and ASCII format to the console. If the
+.I -f
+option is specified, the block number is relative to the start of the given
+.BR filespec .
.TP
-.I cat filespec
-Dump the contents of the inode
+.BI cat " filespec"
+Dump the contents of the inode
.I filespec
to stdout.
.TP
-.I cd filespec
-Change the current working directory to
+.BI cd " filespec"
+Change the current working directory to
.IR filespec .
.TP
-.I chroot filespec
-Change the root directory to be the directory
+.BI chroot " filespec"
+Change the root directory to be the directory
.IR filespec .
.TP
-.I close [-a]
-Close the currently open file system. If the
+.BI close " [-a]"
+Close the currently open file system. If the
.I -a
option is specified, write out any changes to the superblock and block
group descriptors to all of the backup superblocks, not just to the
master superblock.
.TP
-.I clri file
-Clear the contents of the inode
-.IR file .
+.BI clri " filespec"
+Clear the contents of the inode
+.IR filespec .
.TP
-.I dirsearch filespec filename
+.BI dirsearch " filespec filename"
Search the directory
.I filespec
for
.IR filename .
.TP
-.I dump [-p] filespec out_file
-Dump the contents of the inode
+.B dirty
+Mark the filesystem as dirty, so that the superblocks will be written on exit.
+.TP
+.BI dump " [-p] filespec out_file"
+Dump the contents of the inode
.I filespec
-to the output file
-.IR out_file .
-If the
-.I -p
-option is given set the owner, group and permissions information on
-.I out_file
-to match
+to the output file
+.IR out_file .
+If the
+.I -p
+option is given set the owner, group and permissions information on
+.I out_file
+to match
.IR filespec .
.TP
-.I dump_mmp
+.B dump_mmp
Display the multiple-mount protection (mmp) field values.
.TP
-.I dx_hash [-h hash_alg] [-s hash_seed] filename
+.BI dx_hash " [-h hash_alg] [-s hash_seed] filename"
Calculate the directory hash of
.IR filename .
The hash algorithm specified with
.I -h
-may be "legacy" "half_md4" or "tea".
+may be
+.BR legacy , " half_md4" ", or " tea .
The hash seed specified with
.I -s
must be in UUID format.
.TP
-.I dump_extents [-n] [-l] filespec
+.BI dump_extents " [-n] [-l] filespec"
Dump the the extent tree of the inode
.IR filespec .
-The
+The
.I -n
flag will cause
-.I dump_extents
+.B dump_extents
to only display the interior nodes in the extent tree. The
-.I -l
-flag cause
-.I dump_extents
+.I -l
+flag will cause
+.B dump_extents
to only display the leaf nodes in the extent tree.
.IP
(Please note that the length and range of blocks for the last extent in
an interior node is an estimate by the extents library functions, and is
not stored in filesystem data structures. Hence, the values displayed
-may not necessarily by accurate and does not indicate a problem or
+may not necessarily by accurate and does not indicate a problem or
corruption in the file system.)
.TP
-.I expand_dir filespec
+.BI expand_dir " filespec"
Expand the directory
.IR filespec .
.TP
-.I feature [fs_feature] [-fs_feature] ...
+.BI feature " [fs_feature] [-fs_feature] ..."
Set or clear various filesystem features in the superblock. After setting
or clearing any filesystem features that were requested, print the current
state of the filesystem feature set.
.TP
-.I filefrag [-dvr] filespec
+.BI filefrag " [-dvr] filespec"
Print the number of contiguous extents in
.IR filespec .
If
.I filefrag
to do a recursive listing of the directory.
.TP
-.I find_free_block [count [goal]]
-Find the first
+.BI find_free_block " [count [goal]]"
+Find the first
.I count
free blocks, starting from
.I goal
-and allocate it.
+and allocate it. Also available as
+.BR ffb .
.TP
-.I find_free_inode [dir [mode]]
-Find a free inode and allocate it. If present,
+.BI find_free_inode " [dir [mode]]"
+Find a free inode and allocate it. If present,
.I dir
-specifies the inode number of the directory
-which the inode is to be located. The second
+specifies the inode number of the directory
+which the inode is to be located. The second
optional argument
.I mode
specifies the permissions of the new inode. (If the directory bit is set
-on the mode, the allocation routine will function differently.)
+on the mode, the allocation routine will function differently.) Also
+available as
+.BR ffi .
.TP
-.I freeb block [count]
+.BI freeb " block [count]"
Mark the block number
.I block
as not allocated.
-If the optional argument
-.I count
-is present, then
+If the optional argument
+.I count
+is present, then
.I count
blocks starting at block number
.I block
will be marked as not allocated.
.TP
-.I freefrag [-c chunk_kb ]
+.BI freefrag " [-c chunk_kb]"
Report free space fragmentation on the currently open file system.
If the
.I \-c
can be found in the file system. The chunk size must be a power of two
and be larger than the file system block size.
.TP
-.I freei filespec [num]
-Free the inode specified by
+.BI freei " filespec [num]"
+Free the inode specified by
.IR filespec .
If
.I num
is specified, also clear num-1 inodes after the specified inode.
.TP
-.I help
-Print a list of commands understood by
+.B help
+Print a list of commands understood by
.BR debugfs .
.TP
-.I htree_dump filespec
+.BI htree_dump " filespec"
Dump the hash-indexed directory
.IR filespec ,
showing its tree structure.
.TP
-.I icheck block ...
+.BI icheck " block ..."
Print a listing of the inodes which use the one or more blocks specified
on the command line.
.TP
-.I imap filespec
-Print the location of the inode data structure (in the inode table)
+.BI imap " filespec"
+Print the location of the inode data structure (in the inode table)
of the inode
.IR filespec .
.TP
-.I init_filesys device blocksize
+.BI init_filesys " device blocksize"
Create an ext2 file system on
.I device
with device size
.IR blocksize .
-Note that this does not fully initialize all of the data structures;
-to do this, use the
+Note that this does not fully initialize all of the data structures;
+to do this, use the
.BR mke2fs (8)
program. This is just a call to the low-level library, which sets up
the superblock and block descriptors.
.TP
-.I kill_file filespec
-Deallocate the inode
+.BI kill_file " filespec"
+Deallocate the inode
.I filespec
and its blocks. Note that this does not remove any directory
-entries (if any) to this inode. See the
+entries (if any) to this inode. See the
.BR rm (1)
command if you wish to unlink a file.
.TP
-.I lcd directory
+.BI lcd " directory"
Change the current working directory of the
.B debugfs
process to
.I directory
on the native filesystem.
.TP
-.I ln filespec dest_file
-Create a link named
+.BI ln " filespec dest_file"
+Create a link named
.I dest_file
-which is a link to
+which is a hard link to
.IR filespec .
Note this does not adjust the inode reference counts.
.TP
-.I logdump [-acs] [-b<block>] [-i<filespec>] [-f<journal_file>] [output_file]
-Dump the contents of the ext3 journal. By default, the journal inode as
-specified in the superblock. However, this can be overridden with the
+.BI logdump " [-acs] [-b block] [-i filespec] [-f journal_file] [output_file]"
+Dump the contents of the ext3 journal. By default, dump the journal inode as
+specified in the superblock. However, this can be overridden with the
.I \-i
-option, which uses an inode specifier to specify the journal to be
-used. A file containing journal data can be specified using the
+option, which dumps the journal from the internal inode given by
+.IR filespec .
+A regular file containing journal data can be specified using the
.I \-f
-option. Finally, the
+option. Finally, the
.I \-s
option utilizes the backup information in the superblock to locate the
journal.
.IP
-The
+The
.I \-a
-option causes the
-.I logdump
+option causes the
+.B logdump
program to print the contents of all of the descriptor blocks.
-The
+The
.I \-b
-option causes
-.I logdump
-to print all journal records that are refer to the specified block.
-The
+option causes
+.B logdump
+to print all journal records that are refer to the specified block.
+The
.I \-c
option will print out the contents of all of the data blocks selected by
-the
+the
.I \-a
-and
+and
.I \-b
options.
.TP
-.I ls [-l] [-d] [-p] filespec
+.BI ls " [-d] [-l] [-p] filespec"
Print a listing of the files in the directory
.IR filespec .
-The
-.I \-l
-flag will list files using a more verbose format.
The
.I \-d
flag will list deleted entries in the directory.
-The
+The
+.I \-l
+flag will list files using a more verbose format.
+The
.I \-p
flag will list the files in a format which is more easily parsable by
scripts, as well as making it more clear when there are spaces or other
non-printing characters at the end of filenames.
.TP
-.I modify_inode filespec
+.BI modify_inode " filespec"
Modify the contents of the inode structure in the inode
.IR filespec .
+Also available as
+.BR mi .
.TP
-.I mkdir filespec
+.BI mkdir " filespec"
Make a directory.
.TP
-.I mknod filespec [p|[[c|b] major minor]]
+.BI mknod " filespec [p|[[c|b] major minor]]"
Create a special device file (a named pipe, character or block device).
-If a character or block device is to be made, the
+If a character or block device is to be made, the
.I major
and
.I minor
device numbers must be specified.
.TP
-.I ncheck [-c] inode_num ...
+.BI ncheck " [-c] inode_num ..."
Take the requested list of inode numbers, and print a listing of pathnames
to those inodes. The
.I -c
flag will enable checking the file type information in the directory
entry to make sure it matches the inode's type.
.TP
-.I open [-w] [-e] [-f] [-i] [-c] [-D] [-b blocksize] [-s superblock] device
-Open a filesystem for editing. The
-.I -f
-flag forces the filesystem to be opened even if there are some unknown
-or incompatible filesystem features which would normally
+.BI open " [-weficD] [-b blocksize] [-s superblock] device"
+Open a filesystem for editing. The
+.I -f
+flag forces the filesystem to be opened even if there are some unknown
+or incompatible filesystem features which would normally
prevent the filesystem from being opened. The
.I -e
flag causes the filesystem to be opened in exclusive mode. The
.IR -b ", " -c ", " -i ", " -s ", " -w ", and " -D
-options behave the same as the command-line options to
+options behave the same as the command-line options to
.BR debugfs .
.TP
-.I punch filespec start_blk [end_blk]
+.BI punch " filespec start_blk [end_blk]"
Delete the blocks in the inode ranging from
.I start_blk
to
.I symlink filespec target
Make a symbolic link.
.TP
-.I pwd
+.B pwd
Print the current working directory.
.TP
-.I quit
+.B quit
Quit
.B debugfs
.TP
-.I rdump directory destination
+.BI rdump " directory destination"
Recursively dump
.I directory
and all its contents (including regular files, symbolic links, and other
.I destination
which should be an existing directory on the native filesystem.
.TP
-.I rm pathname
-Unlink
+.BI rm " pathname"
+Unlink
.IR pathname .
-If this causes the inode pointed to by
+If this causes the inode pointed to by
.I pathname
to have no other references, deallocate the file. This command functions
as the unlink() system call.
-.I
+.I
.TP
-.I rmdir filespec
+.BI rmdir " filespec"
Remove the directory
.IR filespec .
.TP
-.I setb block [count]
+.BI setb " block [count]"
Mark the block number
.I block
as allocated.
-If the optional argument
-.I count
-is present, then
+If the optional argument
+.I count
+is present, then
.I count
blocks starting at block number
.I block
will be marked as allocated.
.TP
-.I set_block_group bgnum field value
+.BI set_block_group " bgnum field value"
Modify the block group descriptor specified by
.I bgnum
so that the block group descriptor field
.I field
has value
-.I value.
+.IR value .
+Also available as
+.BR set_bg .
.TP
-.I seti filespec [num]
-Mark inode
+.BI seti " filespec [num]"
+Mark inode
.I filespec
as in use in the inode bitmap. If
.I num
is specified, also set num-1 inodes after the specified inode.
.TP
-.I set_inode_field filespec field value
-Modify the inode specified by
+.BI set_inode_field " filespec field value"
+Modify the inode specified by
.I filespec
so that the inode field
.I field
-has value
+has value
.I value.
-The list of valid inode fields which can be set via this command
+The list of valid inode fields which can be set via this command
can be displayed by using the command:
.B set_inode_field -l
+Also available as
+.BR sif .
.TP
-.I set_mmp_value field value
-Modify the multiple-mount protection (mmp) data so that the
-mmp field
+.BI set_mmp_value " field value"
+Modify the multiple-mount protection (MMP) data so that the MMP field
.I field
has value
.I value.
-The list of valid mmp fields which can be set via this command
+The list of valid MMP fields which can be set via this command
can be displayed by using the command:
.B set_mmp_value -l
+Also available as
+.BR smmp .
.TP
-.I set_super_value field value
+.BI set_super_value " field value"
Set the superblock field
.I field
-to
+to
.I value.
-The list of valid superblock fields which can be set via this command
+The list of valid superblock fields which can be set via this command
can be displayed by using the command:
.B set_super_value -l
+Also available as
+.BR ssv .
.TP
-.I show_super_stats [-h]
+.BI show_super_stats " [-h]"
List the contents of the super block and the block group descriptors. If the
.I -h
-flag is given, only print out the superblock contents.
+flag is given, only print out the superblock contents. Also available as
+.BR stats .
.TP
-.I stat filespec
+.BI stat " filespec"
Display the contents of the inode structure of the inode
.IR filespec .
.TP
-.I testb block [count]
+.BI testb " block [count]"
Test if the block number
.I block
is marked as allocated in the block bitmap.
-If the optional argument
-.I count
-is present, then
+If the optional argument
+.I count
+is present, then
.I count
blocks starting at block number
.I block
will be tested.
.TP
-.I testi filespec
-Test if the inode
+.BI testi " filespec"
+Test if the inode
.I filespec
is marked as allocated in the inode bitmap.
.TP
-.I undel <inode num> [pathname]
+.BI undel " <inode_number> [pathname]"
Undelete the specified inode number (which must be surrounded by angle
brackets) so that it and its blocks are marked in use, and optionally
-link the recovered inode to the specified pathname. The
+link the recovered inode to the specified pathname. The
.B e2fsck
-command should always be run after using the
+command should always be run after using the
.B undel
command to recover deleted files.
.IP
Note that if you are recovering a large number of deleted files, linking
the inode to a directory may require the directory to be expanded, which
could allocate a block that had been used by one of the
-yet-to-be-undeleted files. So it is safer to undelete all of the
+yet-to-be-undeleted files. So it is safer to undelete all of the
inodes without specifying a destination pathname, and then in a separate
pass, use the debugfs
.B link
-command to link the inode to the destination pathname, or use
+command to link the inode to the destination pathname, or use
.B e2fsck
to check the filesystem and link all of the recovered inodes to the
lost+found directory.
.TP
-.I unlink pathname
-Remove the link specified by
-.I pathname
+.BI unlink " pathname"
+Remove the link specified by
+.I pathname
to an inode. Note this does not adjust the inode reference counts.
.TP
-.I write source_file out_file
-Create a file in the filesystem named
-.IR out_file ,
-and copy the contents of
+.BI write " source_file out_file"
+Copy the contents of
.I source_file
-into the destination file.
+into a newly-created file in the filesystem named
+.IR out_file .
.TP
-.I zap_block [-f file] [-o offset] [-l length] [-p pattern] block_num
-Zero, or pattern-fill, portions of a block within a file or
-within the filesystem.
+.BI zap_block " [-f filespec] [-o offset] [-l length] [-p pattern] block_num"
.TP
-.I zap_block [-f file] [-b bit] block_num
-Bit-flip portions of a block within a file or
-within the filesystem.
+Overwrite the block specified by
+.I block_num
+with zero (NUL) bytes, or if
+.I -p
+is given use the byte specified by
+.IR pattern .
+If
+.I -f
+is given then
+.I block_num
+is relative to the start of the file given by
+.IR filespec .
+The
+.I -o
+and
+.I -l
+options limit the range of bytes to zap to the specified
+.I offset
+and
+.I length
+relative to the start of the block.
+.TP
+.BI zap_block " [-f filespec] [-b bit] block_num"
+Bit-flip portions of the physical
+.IR block_num .
+If
+.I -f
+is given, then
+.I block_num
+is a logical block relative to the start of
+.IR filespec .
.SH ENVIRONMENT VARIABLES
.TP
.B DEBUGFS_PAGER, PAGER
The
.B debugfs
program always pipes the output of the some commands through a
-pager program. These commands include:
-.IR show_super_stats ,
-.IR list_directory ,
-.IR show_inode_info ,
-.IR list_deleted_inodes ,
+pager program. These commands include:
+.IR show_super_stats " (" stats ),
+.IR list_directory " (" ls ),
+.IR show_inode_info " (" stat ),
+.IR list_deleted_inodes " (" lsdel ),
and
.IR htree_dump .
The specific pager can explicitly specified by the
.B DEBUGFS_PAGER
environment variable, and if it is not set, by the
.B PAGER
-environment variable.
+environment variable.
.IP
-Note that since a pager is always used, the
+Note that since a pager is always used, the
.BR less (1)
pager is not particularly appropriate, since it clears the screen before
displaying the output of the command and clears the output the screen
-when the pager is exited. Many users prefer to use the
+when the pager is exited. Many users prefer to use the
.BR less (1)
-pager for most purposes, which is why the
-.B DEBUGFS_PAGER
+pager for most purposes, which is why the
+.B DEBUGFS_PAGER
environment variable is available to override the more general
.B PAGER
environment variable.
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