chattr changes the file attributes on a Linux second extended file system.
The operator `+' causes the selected attributes to be added to the existing attributes of the files; `-' causes them to be removed; and `=' causes them to be the only attributes that the files have.
Recursively change attributes of directories and their contents. Symbolic links encountered during recursive directory traversals are ignored.
Be verbose with chattr's output and print the program version.
When a file with the 'A' attribute set is modified, its atime record is not modified. This avoids a certain amount of disk I/O for laptop systems.
A file with the `a' attribute set can only be open in append mode for writing. Only the superuser can set or clear this attribute.
A file with the `c' attribute set is automatically compressed on the disk by the kernel. A read from this file returns uncompressed data. A write to this file compresses data before storing them on the disk.
A file with the `d' attribute set is not candidate for backup when the dump(8)? program is run.
A file with the `i' attribute cannot be modified: it cannot be deleted or renamed, no link can be created to this file and no data can be written to the file. Only the superuser can set or clear this attribute.
A file with the `j' attribute has all of its data written to the ext3 journal before being written to the file itself, if the filesystem is mounted with the
When a file with the `s' attribute set is deleted, its blocks are zeroed and written back to the disk.
When a file with the `S' attribute set is modified, the changes are written synchronously on the disk; this is equivalent to the `sync' mount option applied to a subset of the files.
A file with the 't' attribute will not have a partial block fragment at the of the file merged with other files (for those filesystems which support tail-merging). This is necessary for applications such as LILO which read the filesystem directly, and who don't understand tail-merged files.
As of Linux 2.2, the `c', 's', and `u' attribute are not honored by the kernel filesystem code. These attributes will be implemented in a future ext2 fs version.