sqfstar(1)

1SQFSTAR(1)                       User Commands                      SQFSTAR(1)
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NAME

6       sqfstar - tool to create a squashfs filesystem from a tar archive
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SYNOPSIS

9         cat xxx.tar | sqfstar [OPTIONS] FILESYSTEM [exclude files]
10         zcat xxx.tgz | sqfstar [OPTIONS] FILESYSTEM [exclude files]
11         xzcat xxx.tar.xz | sqfstar [OPTIONS] FILESYSTEM [exclude files]
12         zstdcat xxx.tar.zst | sqfstar [OPTIONS] FILESYSTEM [exclude files]
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DESCRIPTION

15       Squashfs  is  a  highly  compressed read-only filesystem for Linux.  It
16       uses either gzip/xz/lzo/lz4/zstd compression to  compress  both  files,
17       inodes  and  directories.   Inodes in the system are very small and all
18       blocks are packed to minimise data overhead. Block sizes  greater  than
19       4K are supported up to a maximum of 1Mbytes (default block size 128K).
20
21       Squashfs is intended for general read-only filesystem use, for archival
22       use (i.e. in cases where a .tar.gz file  may  be  used),  and  in  con‐
23       strained  block device/memory systems (e.g. embedded systems) where low
24       overhead is needed.
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OPTIONS

27   Filesystem build options:
28       -comp COMP
29              select COMP compression. Compressors available: gzip  (default),
30              lzo, lz4, xz, zstd, lzma.
31
32       -b BLOCK_SIZE
33              set  data block to BLOCK_SIZE.  Default 128 Kbytes. Optionally a
34              suffix of K or M can be given to specify Kbytes  or  Mbytes  re‐
35              spectively.
36
37       -reproducible
38              build filesystems that are reproducible (default).
39
40       -not-reproducible
41              build filesystems that are not reproducible.
42
43       -mkfs-time TIME
44              set  filesystem creation timestamp to TIME, which is an unsigned
45              32-bit int indicating seconds since the epoch (1970-01-01).
46
47       -fstime TIME
48              synonym for mkfs-time.
49
50       -all-time TIME
51              set all file timestamps to TIME, which is an unsigned 32-bit int
52              indicating seconds since the epoch (1970-01-01).
53
54       -exports
55              make the filesystem exportable via NFS.
56
57       -no-sparse
58              don't detect sparse files.
59
60       -no-xattrs
61              don't store extended attributes.
62
63       -xattrs
64              store extended attributes (default).
65
66       -noI   do not compress inode table.
67
68       -noId  do not compress the uid/gid table (implied by -noI).
69
70       -noD   do not compress data blocks.
71
72       -noF   do not compress fragment blocks.
73
74       -noX   do not compress extended attributes.
75
76       -no-fragments
77              do not use fragments.
78
79       -no-tailends
80              don't pack tail ends into fragments.
81
82       -no-duplicates
83              do not perform duplicate checking.
84
85       -no-hardlinks
86              do not hardlink files, instead store duplicates.
87
88       -all-root
89              make all files owned by root.
90
91       -root-time TIME
92              set root directory time to TIME.
93
94       -root-mode MODE
95              set root directory permissions to octal MODE.
96
97       -root-uid UID
98              set root directory owner to UID.
99
100       -root-gid GID
101              set root directory group to GID.
102
103       -force-uid UID
104              set all file uids to UID.
105
106       -force-gid GID
107              set all file gids to GID.
108
109   Filesystem filter options:
110       -ef EXCLUDE_FILE
111              list of exclude dirs/files.  One per line.
112
113       -regex Allow   POSIX   regular   expressions  to  be  used  in  exclude
114              dirs/files.
115
116   Sqfstar runtime options:
117       -version
118              print version, licence and copyright message.
119
120       -force force Sqfstar to write to block device or file.
121
122       -exit-on-error
123              treat normally ignored errors as fatal.
124
125       -quiet no verbose output.
126
127       -info  print files written to filesystem.
128
129       -no-progress
130              don't display the progress bar.
131
132       -progress
133              display progress bar when using the -info option.
134
135       -throttle PERCENTAGE
136              throttle the I/O input rate by the given percentage. This can be
137              used to reduce the I/O and CPU consumption of Mksquashfs.
138
139       -limit PERCENTAGE
140              limit  the  I/O  input rate to the given percentage. This can be
141              used to reduce the I/O and CPU consumption of Mksquashfs (alter‐
142              native to -throttle).
143
144       -processors NUMBER
145              Use NUMBER processors.  By default will use number of processors
146              available.
147
148       -mem SIZE
149              Use SIZE physical memory. Optionally a suffix of K, M or  G  can
150              be given to specify Kbytes, Mbytes or Gbytes respectively.
151
152   Expert options (these may make the filesystem unmountable):
153       -nopad do not pad filesystem to a multiple of 4K.
154
155       -offset OFFSET
156              Skip  OFFSET  bytes at the beginning of FILESYSTEM. Optionally a
157              suffix of K, M or G can be given to specify  Kbytes,  Mbytes  or
158              Gbytes respectively. Default 0 bytes.
159
160       -o OFFSET
161              synonym for -offset.
162
163   Miscellaneous options:
164       -root-owned
165              alternative name for -all-root.
166
167       -noInodeCompression
168              alternative name for -noI.
169
170       -noIdTableCompression
171              alternative name for -noId.
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173       -noDataCompression
174              alternative name for -noD.
175
176       -noFragmentCompression
177              alternative name for -noF.
178
179       -noXattrCompression
180              alternative name for -noX.
181
182       -help  output this options text to stdout.
183
184       -h     output this options text to stdout.
185
186       -Xhelp print compressor options for selected compressor.
187

COMPRESSORS AVAILABLE AND COMPRESSOR SPECIFIC OPTIONS

189   gzip (default):
190       -Xcompression-level COMPRESSION-LEVEL
191              COMPRESSION-LEVEL should be 1 .. 9 (default 9).
192
193       -Xwindow-size WINDOW-SIZE
194              WINDOW-SIZE should be 8 .. 15 (default 15).
195
196       -Xstrategy strategy1,strategy2,...,strategyN
197              Compress  using  strategy1,strategy2,...,strategyN  in  turn and
198              choose the best compression. Available strategies: default, fil‐
199              tered, huffman_only, run_length_encoded and fixed.
200
201   lzo:
202       -Xalgorithm ALGORITHM
203              Where  ALGORITHM  is  one  of:  lzo1x_1, lzo1x_1_11, lzo1x_1_12,
204              lzo1x_1_15, lzo1x_999 (default).
205
206       -Xcompression-level COMPRESSION-LEVEL
207              COMPRESSION-LEVEL should be 1 .. 9 (default 8) Only  applies  to
208              lzo1x_999 algorithm.
209
210   lz4:
211       -Xhc   Compress using LZ4 High Compression.
212
213   xz:
214       -Xbcj filter1,filter2,...,filterN
215              Compress  using filter1,filter2,...,filterN in turn (in addition
216              to no filter), and choose the best compression.  Available  fil‐
217              ters: x86, arm, armthumb, powerpc, sparc, ia64.
218
219       -Xdict-size DICT-SIZE
220              Use  DICT-SIZE  as  the XZ dictionary size.  The dictionary size
221              can be specified as a percentage of the block size, or as an ab‐
222              solute value.  The dictionary size must be less than or equal to
223              the block size and 8192  bytes  or  larger.   It  must  also  be
224              storable in the xz header as either 2^n or as 2^n+2^(n+1). Exam‐
225              ple dict-sizes are 75%, 50%, 37.5%, 25%, or 32K, 16K, 8K etc.
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227   zstd:
228       -Xcompression-level COMPRESSION-LEVEL
229              COMPRESSION-LEVEL should be 1 .. 22 (default 15).
230
231   lzma:
232              (no options) (deprecated - no kernel support)
233

ENVIRONMENT

235       SOURCE_DATE_EPOCH
236              If set, this is used as the filesystem creation timestamp.  Also
237              any  file  timestamps  which are after SOURCE_DATE_EPOCH will be
238              clamped    to     SOURCE_DATE_EPOCH.      See     https://repro‐
239              ducible-builds.org/docs/source-date-epoch/ for more information.
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EXAMPLES

242       sqfstar IMAGE.SQFS < archive.tar
243              Create a Squashfs filesystem from the uncompressed tar file "ar‐
244              chive.tar".  Sqfstar will use the default  compressor  (normally
245              gzip), and block size of 128 Kbytes.
246
247       zcat archive.tgz | sqfstar IMAGE.SQFS
248              Create  a  Squashfs filesystem from the compressed tar file "ar‐
249              chive.tgz". Sqfstar will use the  default  compressor  (normally
250              gzip), and block size of 128 Kbytes.
251
252       sqfstar -b 1M -comp zstd IMAGE.SQFS < archive.tar
253              Use  a block size of 1 Mbyte and Zstandard compression to create
254              the filesystem.
255
256       sqfstar -root-uid 0 -root-gid 0 IMAGE.SQFS < archive.tar
257              Tar files do not supply a definition for the root directory, and
258              the  default  is  to make the directory owned/group owned by the
259              user  running  Sqfstar.   The  above  command  sets  the  owner‐
260              ship/group ownership to root.
261
262       sqfstar -root-mode 0755 IMAGE.SQFS < archive.tar
263              The  default  permissions  for the root directory is 0777 (rwxr‐
264              wxrwx).  The above command sets the permissions to  0755  (rwxr-
265              xr-x).
266
267       sqfstar IMAGE.SQFS file1 file2 < archive.tar
268              Exclude file1 and file2 from the tar file when creating filesys‐
269              tem.
270
271       sqfstar IMAGE.SQFS "*.gz" < archive.tar
272              Exclude any files in the top level directory which  matches  the
273              wildcard pattern "*.gz".
274
275       sqfstar IMAGE.SQFS "... *.gz" < archive.tar
276              Exclude  any file which matches the wildcard pattern "*.gz" any‐
277              where within the tar file.   The  initial  "..."  indicates  the
278              wildcard pattern is "non-anchored" and will match anywhere.
279
280       Note:  when  passing wildcarded names to Sqfstar, they should be quoted
281       (as in the above examples), to ensure that they are  not  processed  by
282       the shell.
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AUTHOR

285       Written by Phillip Lougher <phillip@squashfs.org.uk>
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COPYRIGHT

288       Copyright © 2022 Phillip Lougher <phillip@squashfs.org.uk>
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290       This program is free software; you can redistribute it and/or modify it
291       under the terms of the GNU General Public License as published  by  the
292       Free  Software  Foundation;  either  version 2, or (at your option) any
293       later version.
294
295       This program is distributed in the hope that it  will  be  useful,  but
296       WITHOUT  ANY  WARRANTY;  without  even  the  implied  warranty  of MER‐
297       CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  General
298       Public License for more details.
299