chattr

Syntax:

chattr [+|- attribute]... [filename]...

Runs on:

QNX Neutrino

Options:

attribute: The attribute you want to remove (-) or set (+).
filename: The name of a file whose attributes you want to display or manipulate.

Description:

The chattr utility is a front end to the DCMD_FSYS_FILE_FLAGS devctl() command—defined in <sys/dcmd_blk.h>, and described in the Devctl and Ioctl Commands reference—which gets and sets file attributes (that are outside the scope of the POSIX standard). For example, the DOS/FAT filesystem has the concept of “hidden” or “system” files. Such attributes are typically stored as flags in the on-disk inode of each file.

When you invoke chattr with no attributes and a filename (or a list of filenames), it displays the currently set attributes of each file. When you invoke chattr with an attribute (or list of attributes), it applies those modifications to each file.

These attributes are divided into the following classes:

Generic: An attribute that corresponds to a concept that may be shared across multiple filesystem formats (even if implemented in a different manner for each one).
Filesystem-specific: An attribute that has meaning only within a specific filesystem.

It's the responsibility of each io-blk.so filesystem module to map generic attributes to and from their private representation.

For example, a hidden file is a generic concept of a filename that may be hidden from normal user browsing (not displayed by ls) but remains available (to open() by an application) if its name is already known. The representation of this concept varies between filesystems:

For DOS/FAT, it directly corresponds to the “hidden” bit.
For ISO-9660, it's the “existence” bit.

This mapping functionality allows for application abstraction away from a particular on-disk structure (a program can work unchanged against any file on any filesystem). Many filesystem-specific attributes have no corresponding generic concept, and must be manipulated with knowledge of the underlying filesystem structure; the various <sys/fs_*.h> header files contain relevant bit definitions.

Filesystem	Attribute	Bit	Description
Generic	`backup`	FS_FLAGS_BACKUP	The file has been modified and should be backed up.
	`contiguous`	FS_FLAGS_CONTIGUOUS	The file is contiguous.
	`dirty`	FS_FLAGS_DIRTY	The filesystem might be in an inconsistent state.
	`hidden`	FS_FLAGS_HIDDEN	The file is hidden from normal user browsing (not displayed by ls) but remains available (to open() by an application) if its name is already known.
Power-Safe (fs-qnx6.so)	`defrag`	QNX6FS_BG_DEFRAG	Background defragmentation is enabled.
	`hold`	QNX6FS_SNAPSHOT_HOLD	Snapshots are on hold for the file.
	`modified`	QNX6FS_INO_MODIFIED	The inode has been modified.
	`snapshot`	FS_FLAGS_COMMITTING	Snapshots are turned on.
	`used`	QNX6FS_INO_USED	The inode is in use.
fs-udf.so	`archive`		The file has been modified and should be backed up.
	`nonreloc`		The file can't be relocated.
	`setgid`		The file has the `setgid` bit set.
	`setuid`		The file has the `setuid` bit set.
	`sorted`		Directories are sorted.
	`sticky`		The sticky bit is set.
	`stream`		The file is a named stream.
	`system`		The file is used exclusively by the OS and shouldn't be changed or deleted.
	`transform`		The file has been transformed (e.g., by being compressed).
fs-dos.so	`archive`	DOSFS_ARCHIVE	The file has been modified and should be backed up.
	`dir`	DOSFS_DIR	The file is a directory.
	`hidden`	DOSFS_HIDDEN	The file is normally hidden from view.
	`label`	DOSFS_VOLLABEL	The file represents the volume label.
	`lcasebase`	DOSFS_LCASE_BASE	The base filename includes lowercase characters.
	`lcaseext`	DOSFS_LCASE_EXT	The filename's extension includes lowercase characters.
	`rdonly`	DOSFS_RDONLY	The file is read-only.
	`system`	DOSFS_SYSTEM	The file is used exclusively by the OS and shouldn't be changed or deleted.
fs-nt.so	`archive`		The file has been modified and should be backed up.
	`compress`		The file is compressed.
	`device`		The file represents a device.
	`encrypt`		The file is encrypted.
	`hidden`		The file is normally hidden from view.
	`normal`		The file is normal.
	`offline`		The actual file is stored remotely.
	`rdonly`		The file is read-only.
	`sparse`		The file is sparse; nonzero data is allocated on disk, but long strings of zeros aren't.
	`system`		The file is used exclusively by the OS and shouldn't be changed or deleted.
	`temp`		The file is temporary.
fs-mac.so	`alias`		The file is an alias file, a dynamic link to another file.
	`bundle`		The file is a bundle, a directory with a standardized hierarchy that holds executable code and any associated resources.
	`desktop`		The file is located on the desktop.
	`hasicon`		The file has its own customized icon.
	`hiddenext`		The file's extension is hidden.
	`invisible`		The file doesn't appear in dialog box listings or windows.
	`namelock`		You can't rename the file or assign another icon to it.
	`stationery`		The file is a stationery pad; you can use it as a template to create new files, but you can't modify the file itself.

Examples:

List the attributes for a file:

# chattr chattr.c
chattr.c: +backup +contiguous +used +modified

Add to and remove from the attributes for a file:

# chattr -archive +system /fs/dos/autoexec.bat
/fs/dos/autoexec.bat: -archive +system

Turn off snapshots for a Power-Safe (fs-qnx6.so) filesystem:

# chattr -snapshot /fs/qnx6
/fs/qnx6: -snapshot