mkfs.cramfs(8)

1MKFS.CRAMFS(8)               System Administration              MKFS.CRAMFS(8)
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NAME

6       mkfs.cramfs - make compressed ROM file system
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SYNOPSIS

9       mkfs.cramfs [options] directory file
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DESCRIPTION

12       Files on cramfs file systems are zlib-compressed one page at a time to
13       allow random read access. The metadata is not compressed, but is
14       expressed in a terse representation that is more space-efficient than
15       conventional file systems.
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17       The file system is intentionally read-only to simplify its design;
18       random write access for compressed files is difficult to implement.
19       cramfs ships with a utility (mkcramfs(8)) to pack files into new cramfs
20       images.
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22       File sizes are limited to less than 16 MB.
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24       Maximum file system size is a little under 272 MB. (The last file on
25       the file system must begin before the 256 MB block, but can extend past
26       it.)
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ARGUMENTS

29       The directory is simply the root of the directory tree that we want to
30       generate a compressed filesystem out of.
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32       The file will contain the cram file system, which later can be mounted.
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OPTIONS

35       -v
36           Enable verbose messaging.
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38       -E
39           Treat all warnings as errors, which are reflected as command exit
40           status.
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42       -b blocksize
43           Use defined block size, which has to be divisible by page size.
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45       -e edition
46           Use defined file system edition number in superblock.
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48       -N big, little, host
49           Use defined endianness. Value defaults to host.
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51       -i file
52           Insert a file to cramfs file system.
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54       -n name
55           Set name of the cramfs file system.
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57       -p
58           Pad by 512 bytes for boot code.
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60       -s
61           This option is ignored. Originally the -s turned on directory entry
62           sorting.
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64       -z
65           Make explicit holes.
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67       -h, --help
68           Display help text and exit.
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70       -V, --version
71           Print version and exit.
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EXIT STATUS

74       0
75           success
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77       8
78           operation error, such as unable to allocate memory
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REPORTING BUGS

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

88       The mkfs.cramfs command is part of the util-linux package which can be
89       downloaded from Linux Kernel Archive
90       <https://www.kernel.org/pub/linux/utils/util-linux/>.
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94util-linux 2.38                   2022-02-17                    MKFS.CRAMFS(8)