2 .TH CHATTR 1 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
4 chattr \- change file attributes on a Linux second extended file system
20 changes the file attributes on a Linux second extended file system.
22 The format of a symbolic mode is +-=[ASacdisu].
24 The operator `+' causes the selected attributes to be added to the
25 existing attributes of the files; `-' causes them to be removed; and
26 `=' causes them to be the only attributes that the files have.
28 The letters `ASacdijsu' select the new attributes for the files:
29 don't update atime (A), synchronous updates (S), append only (a),
30 compressed (c), no dump (d), immutable (i), data journalling (j),
31 secure deletion (s), and undeletable (u).
35 Recursively change attributes of directories and their contents.
36 Symbolic links encountered during recursive directory traversals are
40 Be verbose with chattr's output and print the program version.
43 Set the file's version/generation number.
45 When a file with the 'A' attribute set is modified, its atime record is
46 not modified. This avoids a certain amount of disk I/O for laptop
49 A file with the `a' attribute set can only be open in append mode for writing.
50 Only the superuser can set or clear this attribute.
52 A file with the `c' attribute set is automatically compressed on the disk
53 by the kernel. A read from this file returns uncompressed data. A write to
54 this file compresses data before storing them on the disk.
56 A file with the `d' attribute set is not candidate for backup when the
60 A file with the `i' attribute cannot be modified: it cannot be deleted or
61 renamed, no link can be created to this file and no data can be written
62 to the file. Only the superuser can set or clear this attribute.
64 A file with the `j' attribute has all of its data written to the ext3
65 journal before being written to the file itself, if the filesystem is
66 mounted with the "data=ordered" or "data=writeback" options. When the
67 filesystem is mounted with the "data=journalled" option all file data
68 is already journalled and this attribute has no effect.
70 When a file with the `s' attribute set is deleted, its blocks are zeroed and
71 written back to the disk.
73 When a file with the `S' attribute set is modified,
74 the changes are written synchronously on the disk; this is equivalent to
75 the `sync' mount option applied to a subset of the files.
77 When a file with the `u' attribute set is deleted, its contents are saved.
78 This allows the user to ask for its undeletion.
82 was written by Remy Card <Remy.Card@linux.org>.
83 .SH BUGS AND LIMITATIONS
84 As of Linux 2.2, the `c', 's', and `u' attribute are not honored
85 by the kernel filesystem code. These attributes will be implemented
86 in a future ext2 fs version.
88 The `j' option is only useful if the filesystem is mounted as ext3.
91 is part of the e2fsprogs package and is available from
92 http://e2fsprogs.sourceforge.net.