mkfs.cramfs(8)

1EXAMPLE(8)                   System Administration                  EXAMPLE(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; ran‐
18       dom  write  access  for  compressed  files  is  difficult to implement.
19       cramfs ships with a utility (mkcramfs) to pack files  into  new  cramfs
20       images.
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22       File sizes are limited to less than 16MB.
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24       Maximum  file  system  size is a little under 272MB.  (The last file on
25       the file system must begin before the 256MB 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     Enable verbose messaging.
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37       -E     Treat all warnings as errors, which  are  reflected  as  command
38              return value.
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40       -b blocksize
41              Use defined block size, which has to be divisible by page size.
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43       -e edition
44              Use defined file system edition number in superblock.
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46       -N big, little, host
47              Use defined endianness.  Value defaults to host.
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49       -i file
50              Insert a file to cramfs file system.
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52       -n name
53              Set name of the cramfs file system.
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55       -p     Pad by 512 bytes for boot code.
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57       -s     This  option  is ignored.  Originally the -s turned on directory
58              entry sorting.
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60       -z     Make explicit holes.  Use of this  option  will  require  2.3.39
61              kernel, or newer.
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63       -V     Display version information and exit.
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65       -h     Display help and exit.
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EXIT STATUS

68              0      success
69              8      operation error, such as unable to allocate memory
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AVAILABILITY

75       The  example command is part of the util-linux package and is available
76       from Linux Kernel  Archive  ⟨ftp://ftp.kernel.org/pub/linux/utils/util-
77       linux/⟩.
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81util-linux                        April 2013                        EXAMPLE(8)