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diff --git a/bin/tar2sqfs/tar2sqfs.1 b/bin/tar2sqfs/tar2sqfs.1 new file mode 100644 index 0000000..da344ec --- /dev/null +++ b/bin/tar2sqfs/tar2sqfs.1 @@ -0,0 +1,154 @@ +.TH TAR2SQFS "1" "June 2019" "tar2sqfs" "User Commands" +.SH NAME +tar2sqfs \- create a SquashFS image from a tar archive +.SH SYNOPSIS +.B tar2sqfs +[\fI\,OPTIONS\/\fR...] \fI\,<sqfsfile>\/\fR +.SH DESCRIPTION +Quickly and painlessly turn a tar ball into a SquashFS filesystem image. +.PP +Possible options: +.TP +\fB\-\-root\-becomes\fR, \fB\-r\fR <dir> +If set, only pack entries that are underneath the specified directory. The +prefix is stripped and the meta data for the directory itself is copied to the +root inode (i.e. the ownership, permissions, extended attributes, +modification time). + +If this option is not set, tar2sqfs implicitly treats \fB./\fR or absolute +paths this way, i.e. if the archive contains an entry for \fB./\fR, it becomes +the root node and the prefix is stripped from all paths (and similar for +absolute paths and \fB/\fR). +.TP +\fB\-\-compressor\fR, \fB\-c\fR <name> +Select the compressor to use. +Run \fBtar2sqfs \-\-help\fR to get a list of all available compressors +and the default selection. +.TP +\fB\-\-comp\-extra\fR, \fB\-X\fR <options> +A comma separated list of extra options for the selected compressor. Specify +\fBhelp\fR to get a list of available options. +.TP +\fB\-\-num\-jobs\fR, \fB\-j\fR <count> +If libsquashfs was compiled with a thread pool based, parallel data +compressor, this option can be used to set the number of compressor +threads. If not set, the default is the number of available CPU cores. +.TP +\fB\-\-queue\-backlog\fR, \fB\-Q\fR <count> +Maximum number of data blocks in the thread worker queue before the packer +starts waiting for the block processors to catch up. Higher values result +in higher memory consumption. Defaults to 10 times the number of workers. +.TP +\fB\-\-block\-size\fR, \fB\-b\fR <size> +Block size to use for SquashFS image. +Defaults to 131072. +.TP +\fB\-\-dev\-block\-size\fR, \fB\-B\fR <size> +Device block size to padd the image to. +Defaults to 4096. +.TP +\fB\-\-defaults\fR, \fB\-d\fR <options> +A comma separated list of default values for +implicitly created directories. +The following values can be set: +.TS +tab(;) allbox; +l l +l l +l l +l l +l l +rd. +\fBOption\fR;\fBDefault\fR +uid=<value>;0 +gid=<value>;0 +mode=<value>;0755 +mtime=<value>;\fB$SOURCE\_DATE\_EPOCH\fR if set, 0 otherwise +.TE +.TP +.TP +\fB\-\-no\-keep\-time\fR, \fB\-k\fR +Replace the time stamps from the tar archive with default time stamps for all +entries. + +The default behavior is to preserve the time stamps from the archive to the +extent possible (SquashFS has second resolution and 32 bit time stamps; tar can +use extensions to specify much larger timestamps with arbitrary precision). The +root inode (unless \fB\-\-root\-becomes\fR is used) and the modification time on +the SquashFS image itself will still be set to defaults. +.TP +\fB\-\-no\-xattr\fR, \fB\-x\fR +Do not copy extended attributes from archive. Default behaviour is to copy all +extended attributes and skip the ones that cannot be encoded in SquashFS. +.TP +\fB\-\-no\-skip\fR, \fB\-s\fR +Abort if a tar record cannot be read instead of skipping it. +.TP +\fB\-\-exportable\fR, \fB\-e\fR +Generate an export table for NFS support. +.TP +\fB\-\-no\-tail\-packing\fR, \fB\-T\fR +Do not perform tail end packing on files that are larger than the +specified block size. +.TP +\fB\-\-force\fR, \fB\-f\fR +Overwrite the output file if it exists. +.TP +\fB\-\-quiet\fR, \fB\-q\fR +Do not print out progress reports. +.TP +\fB\-\-help\fR, \fB\-h\fR +Print help text and exit. +.TP +\fB\-\-version\fR, \fB\-V\fR +Print version information and exit. +.SH COMPATIBILITY +Currently the program can process v7 format, pre-POSIX ustar, POSIX tar and GNU +tar archives. PAX extension headers are also supported. Global PAX headers are +ignored. + +The support for GNU tar is limited to commonly used subset (i.e. some legacy +extensions that GNU tar itself no longer generates are not supported; neither +are mutli volume archives). + +Extended attributes are supported through the SCHILY.xattr PAX extension +(favoured by GNU tar and star) or through the LIBARCHIVE.xattr PAX extension. + +If any unsupported section or extended attribute key is encountered in an +archive, a warning message is written to stderr. If the \fB\-\-no\-skip\fR +option is set, processing aborts. By default, unknown sections and unsupported +extended attributes are simply skipped after issuing a warning. +.SH ENVIRONMENT +If the command line switch \fB\-\-defaults\fR is not used or no default mtime +is specified, the value of the environment variable \fBSOURCE\_DATE\_EPOCH\fR +is used for all file and filesystem timestamps. + +If \fBSOURCE\_DATE\_EPOCH\fR is not set, not a parsable number or it is out of +range, the timestamps default to 0. + +Environment variables are only used if no explicit command line switches +are set. Explicit command line switches are always preferred over the +environment variables. +.SH EXAMPLES +.TP +Turn an uncompressed tar archive into a SquashFS image: +.IP +tar2sqfs rootfs.sqfs < rootfs.tar +.TP +Turn a gzip'ed tar archive into a SquashFS image: +.IP +zcat rootfs.tar.gz | tar2sqfs rootfs.sqfs +.TP +Turn an LZMA2 compressed tar archive into a SquashFS image: +.IP +xzcat rootfs.tar.xz | tar2sqfs rootfs.sqfs +.SH SEE ALSO +gensquashfs(1), rdsquashfs(1), sqfs2tar(1) +.SH AUTHOR +Written by David Oberhollenzer. +.SH COPYRIGHT +Copyright \(co 2019 David Oberhollenzer +License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. +.br +This is free software: you are free to change and redistribute it. +There is NO WARRANTY, to the extent permitted by law. |