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/ext4 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, ext3, or ext4 file system.
43 is the special file corresponding to the device containing the
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
94 number, instead of using the primary superblock (located at an offset of
95 1024 bytes from the beginning of the filesystem). If you specify the
97 option, you must also provide the blocksize of the filesystem via the
104 to read in commands from
106 and execute them. When
108 is finished executing those commands, it will exit.
113 to execute the single command
118 print the version number of
126 as an argument to specify an inode (as opposed to a pathname)
127 in the filesystem which is currently opened by
131 argument may be specified in two forms. The first form is an inode
132 number surrounded by angle brackets, e.g.,
134 The second form is a pathname; if the pathname is prefixed by a forward slash
135 ('/'), then it is interpreted relative to the root of the filesystem
136 which is currently opened by
138 If not, the pathname is
139 interpreted relative to the current working directory as maintained by
141 This may be modified by using the
149 This is a list of the commands which
153 .I bmap filespec logical_block
154 Print the physical block number corresponding to the logical block number
160 Dump the contents of the inode
165 Change the current working directory to
169 Change the root directory to be the directory
173 Close the currently open file system. If the
175 option is specified, write out any changes to the superblock and block
176 group descriptors to all of the backup superblocks, not just to the
180 Clear the contents of the inode
183 .I dump [-p] filespec out_file
184 Dump the contents of the inode
190 option is given set the owner, group and permissions information on
195 .I expand_dir filespec
199 .I feature [fs_feature] [-fs_feature] ...
200 Set or clear various filesystem features in the superblock. After setting
201 or clearing any filesystem features that were requested, print the current
202 state of the filesystem feature set.
204 .I find_free_block [count [goal]]
207 free blocks, starting from
211 .I find_free_inode [dir [mode]]
212 Find a free inode and allocate it. If present,
214 specifies the inode number of the directory
215 which the inode is to be located. The second
218 specifies the permissions of the new inode. (If the directory bit is set
219 on the mode, the allocation routine will function differently.)
221 .I freeb block [count]
222 Mark the block number
225 If the optional argument
229 blocks starting at block number
231 will be marked as not allocated.
234 Free the inode specified by
238 Print a list of commands understood by
242 Print a listing of the inodes which use the one or more blocks specified
246 Print the location of the inode data structure (in the inode table)
250 .I init_filesys device blocksize
251 Create an ext2 file system on
255 Note that this does not fully initialize all of the data structures;
258 program. This is just a call to the low-level library, which sets up
259 the superblock and block descriptors.
261 .I kill_file filespec
264 and its blocks. Note that this does not remove any directory
265 entries (if any) to this inode. See the
267 command if you wish to unlink a file.
270 Change the current working directory of the
274 on the native filesystem.
276 .I ln filespec dest_file
281 Note this does not adjust the inode reference counts.
283 .I logdump [-acs] [-b<block>] [-i<filespec>] [-f<journal_file>] [output_file]
284 Dump the contents of the ext3 journal. By default, the journal inode as
285 specified in the superblock. However, this can be overridden with the
287 option, which uses an inode specifier to specify the journal to be
288 used. A file containing journal data can be specified using the
292 option utilizes the backup information in the superblock to locate the
299 program to print the contents of all of the descriptor blocks.
304 to print all journal records that are refer to the specified block.
307 option will print out the contents of all of the data blocks selected by
314 .I ls [-l] [-d] [-p] filespec
315 Print a listing of the files in the directory
319 flag will list files using a more verbose format.
322 flag will list deleted entries in the directory.
325 flag will list the files in a format which is more easily parsable by
326 scripts, as well as making it more clear when there are spaces or other
327 non-printing characters at the end of filenames.
329 .I modify_inode filespec
330 Modify the contents of the inode structure in the inode
336 .I mknod filespec [p|[[c|b] major minor]]
337 Create a special device file (a named pipe, character or block device).
338 If a character or block device is to be made, the
342 device numbers must be specified.
344 .I ncheck inode_num ...
345 Take the requested list of inode numbers, and print a listing of pathnames
348 .I open [-w] [-e] [-f] [-i] [-c] [-b blocksize] [-s superblock] device
349 Open a filesystem for editing. The
351 flag forces the filesystem to be opened even if there are some unknown
352 or incompatible filesystem features which would normally
353 prevent the filesystem from being opened. The
355 flag causes the filesystem to be opened in exclusive mode. The
356 .IR -b ", " -c ", " -i ", " -s ", and " -w
357 options behave the same as the command-line options to
361 Print the current working directory.
367 .I rdump directory destination
370 and all its contents (including regular files, symbolic links, and other
371 directories) into the named
373 which should be an existing directory on the native filesystem.
378 If this causes the inode pointed to by
380 to have no other references, deallocate the file. This command functions
381 as the unlink() system call.
388 .I setb block [count]
389 Mark the block number
392 If the optional argument
396 blocks starting at block number
398 will be marked as allocated.
400 .I set_block_group bgnum field value
401 Modify the block group descriptor specified by
403 so that the block group descriptor field
411 as in use in the inode bitmap.
413 .I set_inode_field filespec field value
414 Modify the inode specified by
416 so that the inode field
420 The list of valid inode fields which can be set via this command
421 can be displayed by using the command:
422 .B set_inode_field -l
424 .I set_super_value field value
425 Set the superblock field
429 The list of valid superblock fields which can be set via this command
430 can be displayed by using the command:
431 .B set_super_value -l
433 .I show_super_stats [-h]
434 List the contents of the super block and the block group descriptors. If the
436 flag is given, only print out the superblock contents.
439 Display the contents of the inode structure of the inode
442 .I testb block [count]
443 Test if the block number
445 is marked as allocated in the block bitmap.
446 If the optional argument
450 blocks starting at block number
457 is marked as allocated in the inode bitmap.
459 .I undel <inode num> [pathname]
460 Undelete the specified inode number (which must be surrounded by angle
461 brackets) so that it and its blocks are marked in use, and optionally
462 link the recovered inode to the specified pathname. The
464 command should always be run after using the
466 command to recover deleted files.
468 Note that if you are recovering a large number of deleted files, linking
469 the inode to a directory may require the directory to be expanded, which
470 could allocate a block that had been used by one of the
471 yet-to-be-undeleted files. So it is safer to undelete all of the
472 inodes without specifying a destination pathname, and then in a separate
473 pass, use the debugfs
475 command to link the inode to the destination pathname, or use
477 to check the filesystem and link all of the recovered inodes to the
478 lost+found directory.
481 Remove the link specified by
483 to an inode. Note this does not adjust the inode reference counts.
485 .I write source_file out_file
486 Create a file in the filesystem named
488 and copy the contents of
490 into the destination file.
491 .SH ENVIRONMENT VARIABLES
493 .B DEBUGFS_PAGER, PAGER
496 program always pipes the output of the some commands through a
497 pager program. These commands include:
498 .IR show_super_stats ,
500 .IR show_inode_info ,
501 .IR list_deleted_inodes ,
504 The specific pager can explicitly specified by the
506 environment variable, and if it is not set, by the
508 environment variable.
510 Note that since a pager is always used, the
512 pager is not particularly appropriate, since it clears the screen before
513 displaying the output of the command and clears the output the screen
514 when the pager is exited. Many users prefer to use the
516 pager for most purposes, which is why the
518 environment variable is available to override the more general
520 environment variable.
523 was written by Theodore Ts'o <tytso@mit.edu>.