disk-utils/mkfs.cramfs.8

   1 .TH MKFS.CRAMFS 8 "April 2013" "util-linux" "System Administration"
   2 .SH NAME
   3 mkfs.cramfs \- make compressed ROM file system
   4 .SH SYNOPSIS
   5 .B mkfs.cramfs
   6 [options]
   7 .I directory file
   8 .SH DESCRIPTION
   9 Files on cramfs file systems are zlib-compressed one page at a time to
  10 allow random read access.  The metadata is not compressed, but is
  11 expressed in a terse representation that is more space-efficient than
  12 conventional file systems.
  13 .PP
  14 The file system is intentionally read-only to simplify its design; random
  15 write access for compressed files is difficult to implement.  cramfs
  16 ships with a utility (mkcramfs) to pack files into new cramfs images.
  17 .PP
  18 File sizes are limited to less than 16\ MB.
  19 .PP
  20 Maximum file system size is a little under 272\ MB.  (The last file on the
  21 file system must begin before the 256\ MB block, but can extend past it.)
  22 .SH ARGUMENTS
  23 The
  24 .I directory
  25 is simply the root of the directory tree that we want to generate a
  26 compressed filesystem out of.
  27 .PP
  28 The
  29 .I file
  30 will contain the cram file system, which later can be mounted.
  31 .SH OPTIONS
  32 .TP
  33 \fB\-v\fR
  34 Enable verbose messaging.
  35 .TP
  36 \fB\-E\fR
  37 Treat all warnings as errors, which are reflected as command return value.
  38 .TP
  39 \fB\-b\fR \fIblocksize\fR
  40 Use defined block size, which has to be divisible by page size.
  41 .TP
  42 \fB\-e\fR \fIedition\fR
  43 Use defined file system edition number in superblock.
  44 .TP
  45 \fB\-N\fR \fIbig, little, host\fR
  46 Use defined endianness.  Value defaults to
  47 .IR host .
  48 .TP
  49 \fB\-i\fR \fIfile\fR
  50 Insert a
  51 .I file
  52 to cramfs file system.
  53 .TP
  54 \fB\-n\fR \fIname\fR
  55 Set name of the cramfs file system.
  56 .TP
  57 \fB\-p\fR
  58 Pad by 512 bytes for boot code.
  59 .TP
  60 \fB\-s\fR
  61 This option is ignored.  Originally the \-s turned on directory entry
  62 sorting.
  63 .TP
  64 \fB\-z\fR
  65 Make explicit holes.
  66 .TP
  67 \fB\-h\fR, \fB\-\-help\fR
  68 Display help text and exit.
  69 .TP
  70 \fB\-V\fR, \fB\-\-version\fR
  71 Display version information and exit.
  72 .SH "EXIT STATUS"
  73 .RS
  74 .PD 0
  75 .TP
  76 .B 0
  77 success
  78 .TP
  79 .B 8
  80 operation error, such as unable to allocate memory
  81 .PD
  82 .RE
  83 .SH "SEE ALSO"
  84 .BR fsck.cramfs (8),
  85 .BR mount (8)
  86 .SH AVAILABILITY
  87 The example command is part of the util-linux package and is available from
  88 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
  89 Linux Kernel Archive
  90 .UE .