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MKFS.CRAMFS(8)		     System Administration		MKFS.CRAMFS(8)

NAME
       mkfs.cramfs - make compressed ROM file system

SYNOPSIS
       mkfs.cramfs [options] directory file

DESCRIPTION
       Files on	cramfs file systems are	zlib-compressed	one page at a time to
       allow random read access. The metadata is not compressed, but is
       expressed in a terse representation that	is more	space-efficient	than
       conventional file systems.

       The file	system is intentionally	read-only to simplify its design;
       random write access for compressed files	is difficult to	implement.
       cramfs ships with a utility (mkcramfs(8)) to pack files into new	cramfs
       images.

       File sizes are limited to less than 16 MB.

       Maximum file system size	is a little under 272 MB. (The last file on
       the file	system must begin before the 256 MB block, but can extend past
       it.)

ARGUMENTS
       The directory is	simply the root	of the directory tree that we want to
       generate	a compressed filesystem	out of.

       The file	will contain the cram file system, which later can be mounted.

OPTIONS
       -v
	   Enable verbose messaging.

       -E
	   Treat all warnings as errors, which are reflected as	command	exit
	   status.

       -b blocksize
	   Use defined block size, which has to	be divisible by	page size.

       -e edition
	   Use defined file system edition number in superblock.

       -N big, little, host
	   Use defined endianness. Value defaults to host.

       -i file
	   Insert a file to cramfs file	system.

       -n name
	   Set name of the cramfs file system.

       -p
	   Pad by 512 bytes for	boot code.

       -s
	   This	option is ignored. Originally the -s turned on directory entry
	   sorting.

       -z
	   Make	explicit holes.

       -l[=mode]
	   Use exclusive BSD lock for device or	file it	operates. The optional
	   argument mode can be	yes, no	(or 1 and 0) or	nonblock. If the mode
	   argument is omitted,	it defaults to "yes". This option overwrites
	   environment variable	$LOCK_BLOCK_DEVICE. The	default	is not to use
	   any lock at all, but	it's recommended to avoid collisions with
	   udevd or other tools.

       -h, --help
	   Display help	text and exit.

       -V, --version
	   Print version and exit.

EXIT STATUS
       0
	   success

       8
	   operation error, such as unable to allocate memory

SEE ALSO
       fsck.cramfs(8), mount(8)

REPORTING BUGS
       For bug reports,	use the	issue tracker at
       https://github.com/util-linux/util-linux/issues.

AVAILABILITY
       The mkfs.cramfs command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.39.4		  2024-01-31			MKFS.CRAMFS(8)

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