Squashfs

File Format
Name	Squashfs
Ontology	Electronic File Formats Filesystem Squashfs
Extension(s)	.sfs
Wikidata ID	Q389314
Compression	lossless, mandatory
Magic Bytes	68 73 71 73 (little-endian) 73 71 73 68 (big-endian)
Released	2002

Squashfs is a compressed read-only filesystem for Linux. Typically used as a "live image" for booting Linux off a removable storage (e.g. USB, CD/DVD), minus components like the bootloader, kernel and initramfs. It is also used in modern AppImage,, or Snap as a way portable software distribution on Linux. Squashfs can also be used to store other data, such as disk images. Under Windows, Squashfs contents can be opened/extracted via 7-Zip.

See also cramfs.

Identification

SquashFS files created on little-endian machines begins with hexadecimal 68 73 71 73, which translates to "hsqs" in ASCII. SquashFS files created on big-endian machines with hexadecimal 73 71 73 68, which translates to "sqsh" in ASCII.

Examples

Create a Squashfs (file system) image from current/present directory and output it into its parent directory:

 $ mksquashfs . ../example.squashfs -b 1048576 -comp xz -Xdict-size 100%

Open a Squashfs image (as root) from present directory and have its contents visible in /mnt:

 # mount example.squashfs /mnt

Open a Squashfs image (as user) from present directory and have its contents visible in /mnt/temp:

 $ squashfuse example.squashfs /mnt/temp

Software

• 7-Zip
• Squashfuse (Unix-like only)

Sample files

• dexvert samples — archive/squashFS
• Search results for .sfs extension and is squashFS format - Discmaster.textfiles.com

Links

• Wikipedia: SquashFS
• Squashfs website
• SourceForge project page
• GitHub project page
• squashfs.txt