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SQUASHFS 3.0 - A squashed read-only filesystem for Linux
Copyright 2002-2006 Phillip Lougher <>
Released under the GPL licence (version 2 or later).
Welcome to the first release of Squashfs version 3.0. Squashfs 3.0 has the
the following improvements to 2.x.
1. Filesystems are no longer limited to 4 GB. In
theory 2^64 or 4 exabytes is now supported.
2. Files are no longer limited to 4 GB. In theory the maximum
file size is 4 exabytes.
3. Metadata (inode table and directory tables) are no longer
restricted to 16 Mbytes.
4. Hardlinks are now suppported.
5. Nlink counts are now supported.
6. Readdir now returns '.' and '..' entries.
7. Special support for files larger than 256 MB has been added to
the Squashfs kernel code for faster read access.
8. Inode numbers are now stored within the inode rather than being
computed from inode location on disk (this is not so much an
improvement, but a change forced by the previously listed
There is a new Unsquashfs utility (in squashfs-tools) than can be used to
decompress a filesystem without mounting it.
Squashfs 3.0 supports 2.x filesystems. Support for 1.x filesystems
will be added in the future.
Unsquashfs has the following options:
SYNTAX: unsquashfs [-ls | -dest] filesystem
-version print version, licence and copyright information
-info print files as they are unsquashed
-ls list filesystem only
-dest <pathname> unsquash to <pathname>, default "squashfs-root"
The "-ls" option can be used to list the contents of a filesystem without
decompressing the filesystem data itself.
The "-info" option forces Unsquashfs to print each file as it is decompressed.
The "-dest" option specifies the directory that is used to decompress
the filesystem data. If this option is not given then the filesystem is
decompressed to the directory "squashfs-root" in the current working directory.
Unsquashfs can decompress 3.0 filesystems. Support for 2.x and 1.x
filesystems will be added in the future.