2 .\" Copyright 1993, 1994, 1995 by Theodore Ts'o. All Rights Reserved.
3 .\" This file may be copied under the terms of the GNU Public License.
5 .TH DEBUGFS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
7 debugfs \- ext2/ext3 file system debugger
39 program is an interactive file system debugger. It can be used to
40 examine and change the state of an ext2 file system.
43 is the special file corresponding to the device containing the ext2
44 file system (e.g /dev/hdXX).
48 Specifies that the file system should be opened in read-write mode.
49 Without this option, the file system is opened in read-only mode.
52 Specifies that the file system should be opened in catastrophic mode, in
53 which the inode and group bitmaps are not read initially. This can be
54 useful for filesystems with significant corruption, but because of this,
55 catastrophic mode forces the filesystem to be opened read-only.
60 represents an ext2 image file created by the
62 program. Since the ext2 image file only contains the superblock, block
63 group descriptor, block and inode allocation bitmaps, and
66 commands will not function properly.
68 no safety checks are in place, and
70 may fail in interesting ways if commands such as
72 etc. are tried without specifying the
78 is a debugging tool. It has rough edges!
80 .I -d data_source_device
83 option, specifies that
85 should be used when reading blocks not found in the ext2 image file.
86 This includes data, directory, and indirect blocks.
89 Forces the use of the given block size for the file system, rather than
90 detecting the correct block size as normal.
93 Causes the file system superblock to be read from the given block number,
94 rather than the default (1). If you give a
96 option, you must also give a
103 to read in commands from
105 and execute them. When
107 is finished executing those commands, it will exit.
112 to execute the single command
117 print the version number of
125 as an argument to specify an inode (as opposed to a pathname)
126 in the filesystem which is currently opened by
130 argument may be specified in two forms. The first form is an inode
131 number surrounded by angle brackets, e.g.,
133 The second form is a pathname; if the pathname is prefixed by a forward slash
134 ('/'), then it is interpreted relative to the root of the filesystem
135 which is currently opened by
137 If not, the pathname is
138 interpreted relative to the current working directory as maintained by
140 This may be modified by using the
148 This is a list of the commands which
152 .I bmap filespec logical_block
153 Print the physical block number corresponding to the logical block number
159 Dump the contents of the inode
164 Change the current working directory to
168 Change the root directory to be the directory
172 Close the currently open file system.
175 Clear the contents of the inode
178 .I dump [-p] filspec out_file
179 Dump the contents of the inode
185 option is given set the owner, group and permissions information on
190 .I expand_dir filespec
194 .I feature [fs_feature] [-fs_feature] ...
195 Set or clear various filesystem features in the superblock. After setting
196 or clearing any filesystem features that were requested, print the current
197 state of the filesystem feature set.
199 .I find_free_block [count [goal]]
202 free blocks, starting from
206 .I find_free_inode [dir [mode]]
207 Find a free inode and allocate it. If present,
209 specifies the inode number of the directory
210 which the inode is to be located. The second
213 specifies the permissions of the new inode. (If the directory bit is set
214 on the mode, the allocation routine will function differently.)
216 .I freeb block [count]
217 Mark the block number
220 If the optional argument
224 blocks starting at block number
226 will be marked as not allocated.
229 Free the inode specified by
233 Print a list of commands understood by
237 Print a listing of the inodes which use the one or more blocks specified
241 Print the location of the inode data structure (in the inode table)
245 .I init_filesys device blocksize
246 Create an ext2 file system on
250 Note that this does not fully initialize all of the data structures;
253 program. This is just a call to the low-level library, which sets up
254 the superblock and block descriptors.
256 .I kill_file filespec
259 and its blocks. Note that this does not remove any directory
260 entries (if any) to this inode. See the
262 command if you wish to unlink a file.
265 Change the current working directory of the
269 on the native filesystem.
271 .I ln filespec dest_file
276 Note this does not adjust the inode reference counts.
278 .I logdump [-acs] [-b<block>] [-i<filespec>] [-f<journal_file>] [output_file]
279 Dump the contents of the ext3 journal. By default, the journal inode as
280 specified in the superblock. However, this can be overridden with the
282 option, which uses an inode specifier to specify the journal to be
283 used. A file containing journal data can be specified using the
287 option utilizes the backup information in the superblock to locate the
294 program to print the contents of all of the descriptor blocks.
299 to print all journal records that are refer to the specified block.
302 option will print out the contents of all of the data blocks selected by
309 .I ls [-l] [-d] filespec
310 Print a listing of the files in the directory
314 flag will list files using a more verbose format.
317 flag will list deleted entries in the directory.
319 .I modify_inode filespec
320 Modify the contents of the inode structure in the inode
326 .I mknod filespec [p|[[c|b] major minor]]
327 Create a special device file (a named pipe, character or block device).
328 If a character or block device is to be made, the
332 device numbers must be specified.
334 .I ncheck inode_num ...
335 Take the requested list of inode numbers, and print a listing of pathnames
338 .I open [-w] [-e] [-f] [-i] [-c] [-b blocksize] [-s superblock] device
339 Open a filesystem for editing. The
341 flag forces the filesystem to be opened even if there are some unknown
342 or incompatible filesystem features which would normally
343 prevent the filesystem from being opened. The
345 flag causes the filesystem to be opened in exclusive mode. The
346 .IR -b ", " -c ", " -i ", " -s ", and " -w
347 options behave the same as the command-line options to
351 Print the current working directory.
357 .I rdump directory destination
360 and all its contents (including regular files, symbolic links, and other
361 directories) into the named
363 which should be an existing directory on the native filesystem.
368 If this causes the inode pointed to by
370 to have no other references, deallocate the file. This command functions
371 as the unlink() system call.
378 .I setb block [count]
379 Mark the block number
382 If the optional argument
386 blocks starting at block number
388 will be marked as allocated.
390 .I set_block_group bgnum field value
391 Modify the block group descriptor specified by
393 so that the block group descriptor field
401 as in use in the inode bitmap.
403 .I set_inode_field filespec field value
404 Modify the inode specified by
406 so that the inode field
410 The list of valid inode fields which can be set via this command
411 can be displayed by using the command:
412 .B set_inode_field -l
414 .I set_super_value field value
415 Set the superblock field
419 The list of valid superblock fields which can be set via this command
420 can be displayed by using the command:
421 .B set_super_value -l
423 .I show_super_stats [-h]
424 List the contents of the super block and the block group descriptors. If the
426 flag is given, only print out the superblock contents.
429 Display the contents of the inode structure of the inode
432 .I testb block [count]
433 Test if the block number
435 is marked as allocated in the block bitmap.
436 If the optional argument
440 blocks starting at block number
447 is marked as allocated in the inode bitmap.
450 Remove the link specified by
452 to an inode. Note this does not adjust the inode reference counts.
454 .I write source_file out_file
455 Create a file in the filesystem named
457 and copy the contents of
459 into the destination file.
460 .SH ENVIRONMENT VARIABLES
462 .B DEBUGFS_PAGER, PAGER
465 program always pipes the output of the some commands through a
466 pager program. These commands include:
467 .IR show_super_stats ,
469 .IR show_inode_info ,
470 .IR list_deleted_inodes ,
473 The specific pager can explicitly specified by the
475 environment variable, and if it is not set, by the
477 environment variable.
479 Note that since a pager is always used, the
481 pager is not particularly appropriate, since it clears the screen before
482 displaying the output of the command and clears the output the screen
483 when the pager is exited. Many users prefer to use the
485 pager for most purposes, which is why the
487 environment variable is available to override the more general
489 environment variable.
492 was written by Theodore Ts'o <tytso@mit.edu>.