I'm wondering what the output of lsattr means.It prints so oddly as follows,when I have tried: lsattr /usr.
$ lsattr /usr -----------------e- /usr/local -----------------e- /usr/src -----------------e- /usr/games --------------I--e- /usr/include --------------I--e- /usr/share --------------I--e- /usr/lib -----------------e- /usr/lib32 --------------I--e- /usr/bin --------------I--e- /usr/sbin I've read the man page of chattr and lsattr but still have no idea.
The man page for chattr contains all the info you need to understand the lsattr output.
excerpt
The letters 'aAcCdDeFijmPsStTux' select the new attributes for the files: append only (a), no atime updates (A), compressed (c), no copy on write (C), no dump (d), synchronous directory updates (D), extent format (e), case-insensitive directory lookups (F), immutable (i), data journaling (j), don't compress (m), project hierarchy (P), secure deletion (s), synchronous updates (S), no tail-merging (t), top of directory hierarchy (T), undeletable (u), and direct access for files (x).
The following attributes are read-only, and may be listed by lsattr(1) but not modified by chattr: encrypted (E), indexed directory (I), inline data (N), and verity (V).
If you take a look at the descriptions' of the tags further down in that same man page:
The e attribute indicates that the file is using extents for mapping the blocks on disk. It may not be removed using chattr(1).
The I attribute is used by the htree code to indicate that a directory is being indexed using hashed trees. It may not be set or cleared using chattr(1), although it can be displayed by lsattr(1).
From the man page of chattr The ’e’ attribute indicates that the file is using extents for mapping the blocks on disk. It may not be removed using chattr.
An extent is a contiguous area of storage in a computer file system, reserved for a file. When a process creates a file, file-system management software allocates a whole extent. When writing to the file again, possibly after doing other write operations, the data continues where the previous write left off. This reduces or eliminates file fragmentation and possibly file scattering too.
An extent-based file system (i.e., one that addresses storage via extents rather than in single blocks) need not require limiting each file to a single, contiguous extent.
The following systems support extents:
ASM - Automatic Storage Management - Oracle's database-oriented filesystem. BFS - BeOS, Zeta and Haiku operating systems. Btrfs - GPL'd extent based file storage (16PiB/264 max file size). Ext4 - Linux filesystem (when the configuration enables extents — the default in Linux since version 2.6.23). Files-11 - Digital Equipment Corporation (subsequently Hewlett-Packard) OpenVMS filesystem. HFS and HFS Plus - Hierarchical File System - Apple Macintosh filesystems. HPFS - High Performance File Syzstem - OS/2 and eComStation. JFS - Journaled File System - Used by AIX, OS/2/eComStation and Linux operating systems. Microsoft SQL Server - Versions 2000-2008 supports extents of up to 64KB [1]. Multi-Programming Executive - Filesystem by Hewlett-Packard. NTFS - Microsoft's latest-generation file system [1] Reiser4 - Linux filesystem (in "extents" mode). SINTRAN III - File system used by early computer company Norsk Data. UDF - Universal Disk Format - Standard for optical media. VERITAS File System - Enabled via the pre-allocation API and CLI. XFS - SGI's second generation file system.[2] from the wikipedia
chattr and lsattr utilities on Linux and the attributes they manipulate are specific to the Second Extended Filesystem family (ext2, ext3), and are available as part of the e2fsprogs package. They don't work on files residing on other filesystems, e.g. ReiserFS, FAT.
(j) data journalling (t) no tail-merging (e) uses extends for mapping blocks on disk
Normally In the extents filesystem, regular files and directory files are stored as a sequence of extents, contiguous sequences of blocks on a disk. The directory entry for a file keeps track of the file's extents. If the filesystem needs more than one extent to hold a file, it uses a linked list of extent blocks to store information about the extents.
eon a ext3 volume? Really?lsattr -lto print the options using long names instead of single character abbreviations. Also, see this table for a description of individual options.