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)  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 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

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

SEE ALSO

       mount(8), fsck.cramfs(8)

AVAILABILITY

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