sqfstar

TLDR

Create squashfs from tar archive

$ sqfstar < [archive.tar] [filesystem.squashfs]

Create with specific compression

$ zcat [archive.tar.gz] | sqfstar -comp [gzip|lzo|lz4|xz|zstd] [filesystem.squashfs]

Create and exclude files

$ xzcat [archive.tar.xz] | sqfstar [filesystem.squashfs] [file1] [file2]

Exclude by pattern

$ zstdcat [archive.tar.zst] | sqfstar [filesystem.squashfs] "*.gz"

Exclude by regex

$ lz4cat [archive.tar.lz4] | sqfstar [filesystem.squashfs] -regex "[pattern]"

Set block size

$ cat [archive.tar] | sqfstar -b [131072] [filesystem.squashfs]

SYNOPSIS

sqfstar [OPTIONS] FILESYSTEM [excludefiles_...]

sqfstar creates a squashfs filesystem directly from a tar archive read from stdin. Squashfs is a highly compressed read-only filesystem supporting multiple compression algorithms with block sizes from 4K to 1MB.
The tool is useful for converting tar archives to squashfs without intermediate extraction. Compressed tar archives should be decompressed before piping (using zcat, xzcat, etc.). Files can be excluded by name, wildcard pattern, or regex.

PARAMETERS

-comp compressor

Compression algorithm: gzip, lzo, lz4, xz, zstd, lzma

-b blocksize_

Block size in bytes (4K-1MB, default: 128K)

-noI

Do not compress inode table

-noD

Do not compress data blocks

-noF

Do not compress fragment blocks

-no-duplicates

Do not detect duplicate files

-all-root

Make all files owned by root

-force-uid uid

Set all file UIDs

-force-gid gid

Set all file GIDs

-regex

Treat exclude patterns as POSIX regex

-ignore-zeros

Allow concatenated tar archives

-mkfs-time time

Set filesystem creation time

-all-time time

Set all inode timestamps

-processors num

Number of processors to use

-mem size

Set memory limit

-progress

Show progress bar

-info

Print files as they are added

CAVEATS

Input must be tar format; compressed tars need external decompression. Squashfs is read-only after creation. Large archives require significant memory during creation. Block size affects compression ratio and random access performance.

HISTORY

sqfstar is part of squashfs-tools, created by Phillip Lougher. The sqfstar utility was added to provide direct tar-to-squashfs conversion without intermediate files. Squashfs is widely used in Linux distributions for live systems, snap packages, and container images.