{ "content": [ { "type": "text", "text": "# MKFS.CRAMFS (man)\n\n## NAME\n\nmkfs.cramfs - make compressed ROM file system\n\n## SYNOPSIS\n\nmkfs.cramfs [options] directory file\n\n## DESCRIPTION\n\nFiles on cramfs file systems are zlib-compressed one page at a time to allow random read\naccess. The metadata is not compressed, but is expressed in a terse representation that is\nmore space-efficient than conventional file systems.\n\n## TLDR\n\n> Create a ROM filesystem inside a partition.\n\n- Create a ROM filesystem out of a directory inside partition Y on device X:\n `sudo mkfs.cramfs {{path/to/directory}} {{/dev/sdXY}}`\n- Create a ROM filesystem with a volume-name:\n `sudo mkfs.cramfs -n {{volume_name}} {{path/to/directory}} {{/dev/sdXY}}`\n\n*Source: tldr-pages*\n\n## Sections\n\n- **NAME**\n- **SYNOPSIS**\n- **DESCRIPTION**\n- **ARGUMENTS**\n- **OPTIONS** (13 subsections)\n- **EXIT STATUS**\n- **SEE ALSO**\n- **REPORTING BUGS**\n- **AVAILABILITY**\n\nUse structuredContent.sections for detailed options, examples, and full documentation.\n" } ], "structuredContent": { "command": "MKFS.CRAMFS", "section": "", "mode": "man", "summary": "mkfs.cramfs - make compressed ROM file system", "synopsis": "mkfs.cramfs [options] directory file", "tldr_summary": "Create a ROM filesystem inside a partition.", "tldr_examples": [ { "description": "Create a ROM filesystem out of a directory inside partition Y on device X", "command": "sudo mkfs.cramfs {{path/to/directory}} {{/dev/sdXY}}" }, { "description": "Create a ROM filesystem with a volume-name", "command": "sudo mkfs.cramfs -n {{volume_name}} {{path/to/directory}} {{/dev/sdXY}}" } ], "tldr_source": "official", "flags": [ { "flag": "-v", "long": null, "arg": null, "description": "Enable verbose messaging." }, { "flag": "-E", "long": null, "arg": null, "description": "Treat all warnings as errors, which are reflected as command exit status." }, { "flag": "-b", "long": null, "arg": null, "description": "Use defined block size, which has to be divisible by page size." }, { "flag": "-e", "long": null, "arg": null, "description": "Use defined file system edition number in superblock." }, { "flag": "-N", "long": null, "arg": null, "description": "Use defined endianness. Value defaults to host." }, { "flag": "-i", "long": null, "arg": null, "description": "Insert a file to cramfs file system." }, { "flag": "-n", "long": null, "arg": null, "description": "Set name of the cramfs file system." }, { "flag": "-p", "long": null, "arg": null, "description": "Pad by 512 bytes for boot code." }, { "flag": "-s", "long": null, "arg": null, "description": "This option is ignored. Originally the -s turned on directory entry sorting." }, { "flag": "-z", "long": null, "arg": null, "description": "Make explicit holes." }, { "flag": "-l", "long": null, "arg": null, "description": "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 $LOCKBLOCKDEVICE. The default is not to use any lock at all, but it’s recommended to avoid collisions with udevd or other tools." }, { "flag": "-h", "long": "--help", "arg": null, "description": "Display help text and exit." }, { "flag": "-V", "long": "--version", "arg": null, "description": "Print version and exit." } ], "examples": [], "see_also": [ { "name": "fsck.cramfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsck.cramfs/8/json" }, { "name": "mount", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/mount/8/json" } ], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "SYNOPSIS", "lines": 2, "subsections": [] }, { "name": "DESCRIPTION", "lines": 13, "subsections": [] }, { "name": "ARGUMENTS", "lines": 5, "subsections": [] }, { "name": "OPTIONS", "lines": 1, "subsections": [ { "name": "-v", "lines": 2, "flag": "-v" }, { "name": "-E", "lines": 2, "flag": "-E" }, { "name": "-b _", "lines": 2, "flag": "-b" }, { "name": "-e _", "lines": 2, "flag": "-e" }, { "name": "-N _", "lines": 2, "flag": "-N" }, { "name": "-i _", "lines": 2, "flag": "-i" }, { "name": "-n _", "lines": 2, "flag": "-n" }, { "name": "-p", "lines": 2, "flag": "-p" }, { "name": "-s", "lines": 2, "flag": "-s" }, { "name": "-z", "lines": 2, "flag": "-z" }, { "name": "-l", "lines": 5, "flag": "-l" }, { "name": "-h --help", "lines": 2, "flag": "-h", "long": "--help" }, { "name": "-V --version", "lines": 2, "flag": "-V", "long": "--version" } ] }, { "name": "EXIT STATUS", "lines": 6, "subsections": [] }, { "name": "SEE ALSO", "lines": 2, "subsections": [] }, { "name": "REPORTING BUGS", "lines": 2, "subsections": [] }, { "name": "AVAILABILITY", "lines": 4, "subsections": [] } ], "sections": { "NAME": { "content": "mkfs.cramfs - make compressed ROM file system\n", "subsections": [] }, "SYNOPSIS": { "content": "mkfs.cramfs [options] directory file\n", "subsections": [] }, "DESCRIPTION": { "content": "Files on cramfs file systems are zlib-compressed one page at a time to allow random read\naccess. The metadata is not compressed, but is expressed in a terse representation that is\nmore space-efficient than conventional file systems.\n\nThe file system is intentionally read-only to simplify its design; random write access for\ncompressed files is difficult to implement. cramfs ships with a utility (mkcramfs(8)) to pack\nfiles into new cramfs images.\n\nFile sizes are limited to less than 16 MB.\n\nMaximum file system size is a little under 272 MB. (The last file on the file system must\nbegin before the 256 MB block, but can extend past it.)\n", "subsections": [] }, "ARGUMENTS": { "content": "The directory is simply the root of the directory tree that we want to generate a compressed\nfilesystem out of.\n\nThe file will contain the cram file system, which later can be mounted.\n", "subsections": [] }, "OPTIONS": { "content": "", "subsections": [ { "name": "-v", "content": "Enable verbose messaging.\n", "flag": "-v" }, { "name": "-E", "content": "Treat all warnings as errors, which are reflected as command exit status.\n", "flag": "-E" }, { "name": "-b _", "content": "Use defined block size, which has to be divisible by page size.\n", "flag": "-b" }, { "name": "-e _", "content": "Use defined file system edition number in superblock.\n", "flag": "-e" }, { "name": "-N _", "content": "Use defined endianness. Value defaults to host.\n", "flag": "-N" }, { "name": "-i _", "content": "Insert a file to cramfs file system.\n", "flag": "-i" }, { "name": "-n _", "content": "Set name of the cramfs file system.\n", "flag": "-n" }, { "name": "-p", "content": "Pad by 512 bytes for boot code.\n", "flag": "-p" }, { "name": "-s", "content": "This option is ignored. Originally the -s turned on directory entry sorting.\n", "flag": "-s" }, { "name": "-z", "content": "Make explicit holes.\n", "flag": "-z" }, { "name": "-l", "content": "Use exclusive BSD lock for device or file it operates. The optional argument mode can be\nyes, no (or 1 and 0) or nonblock. If the mode argument is omitted, it defaults to \"yes\".\nThis option overwrites environment variable $LOCKBLOCKDEVICE. The default is not to use\nany lock at all, but it’s recommended to avoid collisions with udevd or other tools.\n", "flag": "-l" }, { "name": "-h --help", "content": "Display help text and exit.\n", "flag": "-h", "long": "--help" }, { "name": "-V --version", "content": "Print version and exit.\n", "flag": "-V", "long": "--version" } ] }, "EXIT STATUS": { "content": "0\nsuccess\n\n8\noperation error, such as unable to allocate memory\n", "subsections": [] }, "SEE ALSO": { "content": "fsck.cramfs(8), mount(8)\n", "subsections": [] }, "REPORTING BUGS": { "content": "For bug reports, use the issue tracker at \u001b[34mhttps://github.com/util-linux/util-linux/issues\u001b[0m.\n", "subsections": [] }, "AVAILABILITY": { "content": "The mkfs.cramfs command is part of the util-linux package which can be downloaded from \u001b[34mLinux\u001b[0m\n\u001b[34mKernel Archive \u001b[0m.\n\nutil-linux 2.39.3 2023-11-21 MKFS.CRAMFS(8)", "subsections": [] } } } }