GENEXT2FS(8)						      System Manager's Manual						      GENEXT2FS(8)

NAME

       genext2fs - ext2 filesystem generator for embedded systems

SYNOPSIS

       genext2fs [ options ] [ output-image ]

DESCRIPTION

       genext2fs  generates  an  ext2 filesystem as a normal (non-root) user. It does not require you to mount the image file to copy files on it,
       nor does it require that you become the superuser to make device nodes.

       The filesystem image is created in the file output-image. If not specified, it is sent to stdout.

       By default, the maximum number of inodes in the filesystem is the minimum number required to accommodate the  initial  contents.   In  this
       way,  a minimal filesystem (typically read-only) can be created with minimal free inodes.  If required, free inodes can be added by passing
       the relevant options.  The filesystem image size in blocks can be minimised by trial and error.

OPTIONS

       -x, --starting-image image
	      Use this image as a starting point.

       -d, --root directory[:path]
	      Add the given directory and contents at a particular path (by default the root).

       -D, --devtable spec-file[:path]
	      Use spec-file to specify inodes to be added, at the given path (by default the root), including files, directories and special files
	      like  devices.   If  the	specified  files  are  already present in the image, their ownership and permission modes will be adjusted
	      accordingly.  Furthermore, you can use a single table entry to create many devices with a  range	of  minor  numbers  (see  examples
	      below).  All specified inodes receive the mtime of spec-file itself.

       -b, --size-in-blocks blocks
	      Size of the image in blocks.

       -N, --number-of-inodes inodes
	      Maximum number of inodes.

       -i, --bytes-per-inode ratio
	      Used to calculate the maximum number of inodes from the available blocks.

       -m, --reserved-percentage
	      Number of reserved blocks as a percentage of size. Reserving 0 blocks will prevent creation of the "lost+found" directory.

       -g, --block-map path
	      Generate a block map file for this path.

       -e, --fill-value value
	      Fill unallocated blocks with value.

       -z, --allow-holes
	      Make files with holes.

       -f, --faketime
	      Use a timestamp of 0 for inode and filesystem creation, instead of the present. Useful for testing.

       -q, --squash
	      Squash permissions and owners (same as -P -U).

       -U, --squash-uids
	      Squash ownership of inodes added using the -d option, making them all owned by root:root.

       -P, --squash-perms
	      Squash permissions of inodes added using the -d option. Analogous to "umask 077".

       -v, --verbose
	      Print resulting filesystem structure.

       -V, --version
	      Print genext2fs version.

       -h, --help
	      Display help.

EXAMPLES

       genext2fs -b 1440 -d src /dev/fd0

       All files in the src directory will be written to /dev/fd0 as a new ext2 filesystem image. You can then mount the floppy as usual.

       genext2fs -b 1024 -d src -D device_table.txt flashdisk.img

       This  example  builds  a  filesystem  from all the files in src, then device nodes are created based on the contents of the file device_ta-
       ble.txt.  Entries in the device table take the form of:

       <name> <type> <mode> <uid> <gid> <major> <minor> <start> <inc> <count>

       where name is the file name and type can be one of:
	      f    A regular file
	      d    Directory
	      c    Character special device file
	      b    Block special device file
	      p    Fifo (named pipe)
       uid is the user id for the target file, gid is the group id for the target file.  The rest of the entries (major, minor, etc) apply only to
       device special files.

       An example device file follows:

	      # name	type mode uid gid major minor start inc count

	      /dev	d    755  0    0    -	 -    -    -	-
	      /dev/mem	c    640  0    0    1	 1    0    0	-
	      /dev/tty	c    666  0    0    5	 0    0    0	-
	      /dev/tty	c    666  0    0    4	 0    0    1	6
	      /dev/loop b    640  0    0    7	 0    0    1	2
	      /dev/hda	b    640  0    0    3	 0    0    0	-
	      /dev/hda	b    640  0    0    3	 1    1    1	16
	      /dev/log	s    666  0    0    -	 -    -    -	-

       This  device  table  creates  the  /dev	directory,  a  character  device  node	/dev/mem  (major  1,  minor 1), and also creates /dev/tty,
       /dev/tty[0-5], /dev/loop[0-1], /dev/hda, /dev/hda1 to /dev/hda15 and /dev/log socket.

SEE ALSO

       mkfs(8), genromfs(8), mkisofs(8), mkfs.jffs2(1)

AUTHOR

       This manual page was written by David Kimdon <dwhedon@debian.org>, for the Debian GNU/Linux system (but may be used by  others).   Examples
       provided by Erik Andersen <andersen@codepoet.org>.

								  August 19, 2006						      GENEXT2FS(8)