DEBUGFS(8)
NAME
debugfs - ext2 file system debugger
SYNOPSIS
debugfs [ -w ] [ -f cmd_file ] [ -R request ] [ device ]
DESCRIPTION
The debugfs program is a file system debugger. It can be
used to examine and change the state of an ext2 file sys-
tem.
device is the special file corresponding to the device
containing the ext2 file system (e.g /dev/hdXX).
OPTIONS
-w Specify that the file system should be open in
read-write mode. Without this option, the file sys-
tem is open in read-only mode.
-f cmd_file
Causes debugfs to read in commands from cmd_file,
and execute them. When debugfs is finsihed execut-
ing those commands, it will exit.
-R request
Causes debugfs to execute the single command
request, and then exit.
COMMANDS
debugfs is an interactive debugger. It understands a num-
ber of commands.
cat filespec
Dump the contents of the inode filespec to stdout.
cd filespec
Change the current working directory to filespec.
chroot filespec
Change the root directory to be the directory file-
spec.
close Close the currently open file system.
clri file
Clear the contents of the inode file.
dump [-p] filspec out_file
Dump the contents of the inode filespec to the out-
put file out_file. If the -p option is given set
the owner, group and permissions information on
out_file to match filespec.
expand_dir filespec
Expand the directory filespec.
find_free_block [goal]
Find the first free block, starting from goal and
allocates it.
find_free_inode [dir [mode]]
Find a free inode and allocates it. If present,
dir specifies the inode number of the directory
which the inode is to be located. The second
optional argument mode specifies the permissions of
the new inode. (If the directory bit is set on the
mode, the allocation routine will function differ-
ently.)
freeb block
Mark the block number block as not allocated.
freei filespec
Free the inode specified by filespec
help Print a list of commands understood by debugfs(8).
icheck block ...
Print a listing of the inodes which use the one or
more block specified on the command line.
initialize device blocksize
Create an ext2 file system on device with device
size blocksize. Note that this does not fully ini-
tialize all of the data structures; to do this, use
the mke2fs(8) program. This is just a call to the
low-level library, which sets up the superblock and
block descriptors.
kill_file filespec
Dellocate the inode filespec and its blocks. Note
that this does not remove any directory entries (if
any) to this inode. See the rm command if you wish
to unlink a file.
ln filespec dest_file
Create a link named dest_file which is a link to
filespec. Note this does not adjust the inode ref-
erence counts.
ls [-l] filespec
Print a listing of the files in the directory file-
spec.
modify_inode filespec
Modify the contents of the inode structure in the
inode filespec.
mkdir filespec
Make a directory.
mknod filespec [p|[[c|b] major minor]]
Create a special device file (a named pipe, charac-
ter or block device). If a character or block
device is to be made, the major and minor device
numbers must be specified.
ncheck inode_num ...
Take the requested list of inode numbers, and print
a listing of pathnams to those inodes.
open [-w] device
Open a file system for editing.
pwd Print the current working directory.
quit Quit debugfs
rm pathname
Unlink pathname. If this cuases the inode pointed
to by pathname to have no other references, deallo-
cate the file. This command functions as the
unlink() system call.
rmdir filespec
Remove the directory filespec. This function is
currently not implemented.
setb block
Mark the block number block as allocated.
seti filespec
Mark inode filespec as in use in the inode bitmap.
show_super_stats
List the contents of the super block.
stat filespec
Display the contents of the inode structure of the
inode filespec.
testb block
Test if the block number block is marked as allo-
cated in the block bitmap.
testi filespec
Test if the inode filespec is marked as allocated
in the inode bitmap.
unlink pathname
Remove the link specified by pathname to an inode.
Note this does not adjust the inode reference
counts.
write source_file out_file
Create a file in the filesystem named out_file, and
copy the contents of source_file into the destina-
tion file.
SPECIFYING FILES
Many debugfs commands take a filespec as an argument to
specify an inode (as opposed to a pathname) in the
filesystem which is currently opened by debugfs. The file-
spec argument may be specified in two forms. The first
form is an inode number surrounded by angle brackets,
e.g., <2>. The second form is a pathname; if the pathname
is prefixed by a forward slash ('/'), then it is inter-
preted relative to the root of the filesystem which is
currently opened by debugfs. If not, the pathname is
interpreted relative to the current working directory as
maintained by debugfs. This may be modified by using the
debugfs command cd.
AUTHOR
debugfs was written by Theodore Ts'o lt;tytso@mit.edu.
SEE ALSO
dumpe2fs(8) e2fsck(8) mke2fs(8)