NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | OPTIONS | EXIT STATUS | SEE ALSO | AVAILABILITY | COLOPHON

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

NAME         top

       mkfs.cramfs - make compressed ROM file system

SYNOPSIS         top

       mkfs.cramfs [options] directory file

DESCRIPTION         top

       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) 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         top

       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         top

       -v     Enable verbose messaging.

       -E     Treat all warnings as errors, which are reflected as command
              return value.

       -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.  Use of this option will require 2.3.39
              kernel, or newer.

       -V     Display version information and exit.

       -h     Display help and exit.

EXIT STATUS         top

              0      success
              8      operation error, such as unable to allocate memory

SEE ALSO         top

       fsck.cramfs(8), mount(8)

AVAILABILITY         top

       The example command is part of the util-linux package and is
       available from Linux Kernel Archive 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2017-03-13.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

util-linux                       April 2013                   MKFS.CRAMFS(8)