SIMPLE SOLUTIONS

MKFS.CRAMFS(8) - Linux man page online | Administration and privileged commands

Make compressed ROM file system.

Chapter
April 2013
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) 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 com‐ pressed 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. -h, --help Display help text and exit. -V, --version Display version information and exit.

EXIT STATUS

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

SEE ALSO

fsck.cramfs(8), mount(8)

AVAILABILITY

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/⟩.
util-linux April 2013 MKFS.CRAMFS(8)
This manual Reference Other manuals
mkfs.cramfs(8) referred by fsck.cramfs(8) | systemd-makefs@.service(8)
refer to fsck.cramfs(8) | mount(8)
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