SQFSTAR(1) User Commands SQFSTAR(1) (NAME) sqfstar - squashfs tar (SYNOPSIS) cat xxx.tar | sqfstar [OPTIONS] FILESYSTEM [exclude files] zcat xxx.tgz | sqfstar [OPTIONS] FILESYSTEM [exclude files] xzcat xxx.tar.xz | sqfstar [OPTIONS] FILESYSTEM [exclude files] zstdcat xxx.tar.zst | sqfstar [OPTIONS] FILESYSTEM [exclude files] (DESCRIPTION) Squashfs . gzip/xz/lzo/lz4/zstd inode . inode . 4K 1Mbytes ( 128K ). Squashfs ( .tar.gz ) / ( ) . (OPTIONS) (Filesystem compression options): -b BLOCK-SIZE BLOCK-SIZE. 128 Kbytes . K KB Kbytes M MB Mbytes Kbytes Mbytes . -comp COMP COMP. COMP -help-comp COMP ALL . : gzip () lzo lz4 xz zstd lzma. -noI inode . -noId uid/gid ( -noI ). -noD . -noF (fragment blocks) . -noX (extended attributes) . -no-compression . -noI -noD -noF -noX . (Filesystem build options): -exports NFS . -no-sparse (sparse files) . -no-fragments (fragments) . -no-tailends . -no-duplicates . -no-hardlinks (hardlink) . -regex POSIX / . -ignore-zeros tar Sqfstar . tar EOF Sqfstar tar . Sqfstar . -ef EXCLUDE-FILE / . . (Filesystem time options): -mkfs-time TIME TIME. TIME "inode" inode (1970-01-01) "date" . date "now" "last week" "Wed Feb 15 21:02:39 GMT 2023". -inode-time TIME TIME. TIME "inode" inode (1970-01-01) "date" . date "now" "last week" "Wed Feb 15 21:02:39 GMT 2025". -root-time . -root-time TIME TIME. TIME "inode" inode (1970-01-01) "date" . date "now" "last week" "Wed Feb 15 21:02:39 GMT 2025". -repro (reproducible). -mkfs-time inode inode . . -repro-time TIME . -mkfs-time TIME -inode-time TIME TIME . -repro ..SS " :" -all-root root . -root-mode MODE MODE . MODE ( << >> ). ugo=rwx 0777 . -root-uid USER USER USER uid . -root-gid GROUP GROUP GROUP gid . -force-file-mode MODE () MODE . MODE ( << >> ). -force-dir-mode MODE MODE . MODE ( << >> ). -force-uid USER (uid) USER USER uid . -force-gid GROUP (gid) GROUP GROUP gid . -uid-gid-offset VALUE uid gid VALUE (offset) . VALUE . -default-mode MODE tar . MODE . MODE ( << >> ). u=rwx,go=rx 0755 . . -default-uid USER tar uid . Sqfstar USER . USER uid . uid . -default-gid GROUP tar gid . Sqfstar GROUP . GROUP gid . gid . -numeric-owner uid gid tarfile . Sqfstar uid gid . : -p PSEUDO-DEFINITION (pseudo file) . . << >> . -pd "d mode uid gid" . . . -pd "D time mode uid gid" . D mode uid gid (timestamp) . -pf PSEUDO-FILE . pseudo-file . -pseudo-override uid gid -all-root -force-uid -force-gid . (xattrs) : -no-xattrs . -xattrs (). -xattrs-exclude REGEX xattr REGEX . REGEX POSIX -xattrs-exclude '^user.' xattr user . -xattrs-include REGEX xattr REGEX . REGEX POSIX -xattrs-include '^user.' xattr user . -xattrs-add NAME=VAL xattr NAME VAL . xattr (user) ( man 7 xattr ). . VAL ( ) 0s base64 0x . 0t ASCII . xattr . Sqfstar: -version . -force Sqfstar (block device) . -exit-on-error . -quiet . -info stdout . . -info-file . -info-file FILE FILE . . -no-progress . -progress -info . -percentage . dialog --gauge . -throttle PERCENTAGE I/O (throttle). I/O CPU Sqfstar . -limit PERCENTAGE I/O . I/O CPU Sqfstar ( -throttle). -processors NUMBER NUMBER . . -mem SIZE SIZE () . K M G . -mem-percent PERCENT PERCENT . 25% . -mem-default . -overcommit PERCENT PERCENT (thread) . CPU . 0% (overcommitting) (thrashing) . (granularity) ..SS " ( ):" -stream STDOUT . (pipe) ssh . Squashfs (super block) . -fix Unsquashfs 4.7.3 . -stream . -fix FILESYSTEM FILESYSTEM -stream. -nopad 4K () . -offset OFFSET OFFSET FILESYSTEM. K M G . 0 . -o OFFSET -offset. : -help ( stdout ). -help-option REGEX REGEX ( stdout ). -help-section SECTION SECTION ( stdout ). SECTION (regular expression) . "list" . -help-comp COMP COMP. "list" "all" . -help-all Sqfstar ( stdout ). -Xhelp . -h -help. -ho REGEX -help-option. -hs SECTION -help-section. -ha -help-all. -no-pager (pager) . -cols WIDTH WIDTH . . : -fstime TIME mkfs-time. -root-owned -all-root. -noInodeCompression -noI. -noIdTableCompression -noId. -noDataCompression -noD. -noFragmentCompression -noF. -noXattrCompression -noX. (PSEUDO FILE DEFINITION FORMAT) -p "filename d mode uid gid" . -p "filename m mode uid gid" filename. -p "filename b mode uid gid major minor" . -p "filename c mode uid gid major minor" . -p "filename f mode uid gid command" (stdout) command. -p "filename s mode uid gid symlink" . -p "filename i mode uid gid [s|f]" (s) FIFO (f). -p "filename x name=val" (extended attribute). -p "filename h linkname" linkname . -p "filename l linkname" linkname. -p "filename L pseudo_filename" (pseudo file). -p "filename D time mode uid gid" time. -p "filename M time mode uid gid" time. -p "filename B time mode uid gid major minor" time. -p "filename C time mode uid gid major minor" time. -p "filename F time mode uid gid command" time. -p "filename S time mode uid gid symlink" time. -p "filename I time mode uid gid [s|f]" FIFO time..SH " (SYMBOLIC MODE SPECIFICATION)" [ugoa]*[[+-=]PERMS]+ . PERMS = [rwxXst]+ [ugo] . ugoa u (user) g (group) o (other) a ugo . + - = . + - = . (PERMS) [rwxXst] ugoa // r w x / . X : x . s t (restricted deletion) (sticky) . u g o . (EXIT STATUS) 0 Sqfstar . 1 Sqfstar . (COMPRESSORS AVAILABLE AND COMPRESSOR SPECIFIC OPTIONS) gzip (): -Xcompression-level COMPRESSION-LEVEL COMPRESSION-LEVEL .. ( ). -Xwindow-size WINDOW-SIZE WINDOW-SIZE .. ( ). -Xstrategy strategy1,strategy2,...,strategyN strategy1,strategy2,...,strategyN . : default, filtered, huffman_only, run_length_encoded fixed. lzo: -Xalgorithm ALGORITHM ALGORITHM : lzo1x_1, lzo1x_1_11, lzo1x_1_12, lzo1x_1_15, lzo1x_999 (). -Xcompression-level COMPRESSION-LEVEL COMPRESSION-LEVEL .. ( ). lzo1x_999 . lz4: -Xhc LZ4 High Compression. xz: -Xbcj filter1,filter2,...,filterN filter1,filter2,...,filterN ( ) . : x86, arm, armthumb, arm64, powerpc, sparc, ia64, riscv. -Xdict-size DICT-SIZE DICT-SIZE XZ. . . xz 2^n 2^n+2^(n+1) . dict-size : 75%, 50%, 37.5%, 25% 32K, 16K, 8K . zstd: -Xcompression-level COMPRESSION-LEVEL COMPRESSION-LEVEL -131072 .. -1 .. ( ). --fast zstd . lzma: ( ) ( - ) (ENVIRONMENT) SQFS_CMDLINE sqfs_cmdline Sqfstar . . . SOURCE_DATE_EPOCH . SOURCE_DATE_EPOCH SOURCE_DATE_EPOCH . . PAGER . . /usr/bin/pager . (EXAMPLES) sqfstar IMAGE.SQFS < archive.tar Squashfs tar "archive.tar". Sqfstar ( gzip) . zcat archive.tgz | sqfstar IMAGE.SQFS Squashfs tar "archive.tgz". Sqfstar ( gzip) . sqfstar -b 1M -comp zstd IMAGE.SQFS < archive.tar Zstandard . sqfstar -root-uid 0 -root-gid 0 IMAGE.SQFS < archive.tar tar / Sqfstar . / root . sqfstar -root-mode 0755 IMAGE.SQFS < archive.tar 0777 (rwxrwxrwx) . 0755 (rwxr-xr-x) . sqfstar -all-time now IMAGE.SQFS < archive.tar "now" ( ) . sqfstar -force-uid phillip -force-gid phillip IMAGE.SQFS < archive.tar "phillip". sqfstar -force-file-mode ugo+r,go-w IMAGE.SQFS < archive.tar . sqfstar IMAGE.SQFS file1 file2 < archive.tar file1 file2 tar . sqfstar IMAGE.SQFS "*.gz" < archive.tar "*.gz" . sqfstar IMAGE.SQFS "... *.gz" < archive.tar "*.gz" tar . "..." <<>> . : Sqfstar ( ) ..SS sqfstar -p "build_dir d 0644 0 0" IMAGE.SQFS < archive.tar <> . sqfstar -p "version.txt l /tmp/build/version" IMAGE.SQFS < archive.tar <> tar tar . sqfstar -p "date.txt f 0644 0 0 date" IMAGE.SQFS < archive.tar <> (stdout) <> . sqfstar -p "\"hello world\" f 0644 0 0 date" IMAGE.SQFS < archive.tar . . sqfstar -p "input f 0644 root root dd if=/dev/sda1 bs=1024" IMAGE.SQFS < archive.tar /dev/sda1. Squashfs . : ( ) Mksquashfs . (AUTHORS) Phillip Lougher (COPYRIGHT) (C) 2026 Phillip Lougher (GNU General Public License) ( ) . . . (SEE ALSO) mksquashfs(1), unsquashfs(1), sqfscat(1) README Squashfs-tools 4.7.5 https://github.com/plougher/squashfs-tools/blob/master/Documentation/4.7.5/README.md Sqfstar https://github.com/plougher/squashfs-tools/blob/master/Documentation/4.7.5/USAGE-SQFSTAR.md CHANGELOG Squashfs https://github.com/plougher/squashfs-tools/blob/master/CHANGES.md sqfstar version 4.7.5 March 2026 SQFSTAR(1)