mkfs.cramfs - make compressed ROM file system

       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.

       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 2.40.2                                  2024-04-24                                     MKFS.CRAMFS(8)

       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.)

0
           success

       8
           operation error, such as unable to allocate memory

       mkfs.cramfs - make compressed ROM file system

-v
           Enable verbose messaging.

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

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

       -eedition
           Use defined file system edition number in superblock.

       -Nbig,little,host
           Use defined endianness. Value defaults to host.

       -ifile
           Insert a file to cramfs file system.

       -nname
           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.

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

fsck.cramfs(8), mount(8)

mkfs.cramfs [options] directoryfile