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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2020-09-24 20:19:52 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2020-09-29 18:19:53 +0200
commit30e8abe86cc604672dff3896cdea2a75ed622a4f (patch)
tree8d864199f70e89364e01621b12fca9f336c6c253 /bin/sqfs2tar
parent4b4cee0c0c99f531a45157fd27f5441e511db109 (diff)
Update tar2sqfs/sqfs2tar documentation
Modify the man pages and help texts to mention compression support, make the help option display a list of supported compressors. Also clarify the squashfs compressor list in the help text to state that the list shows block compressors supported for SquashFS compression. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'bin/sqfs2tar')
-rw-r--r--bin/sqfs2tar/options.c8
-rw-r--r--bin/sqfs2tar/sqfs2tar.121
2 files changed, 18 insertions, 11 deletions
diff --git a/bin/sqfs2tar/options.c b/bin/sqfs2tar/options.c
index 356913a..a84fcd4 100644
--- a/bin/sqfs2tar/options.c
+++ b/bin/sqfs2tar/options.c
@@ -62,13 +62,7 @@ static const char *usagestr =
" --help, -h Print help text and exit.\n"
" --version, -V Print version information and exit.\n"
"\n"
-"Examples:\n"
-"\n"
-"\tsqfs2tar rootfs.sqfs > rootfs.tar\n"
-"\tsqfs2tar rootfs.sqfs | gzip > rootfs.tar.gz\n"
-"\tsqfs2tar rootfs.sqfs | xz > rootfs.tar.xz\n"
-"\n"
-"Available compressors:\n";
+"Supported tar compression formats:\n";
bool dont_skip = false;
bool keep_as_dir = false;
diff --git a/bin/sqfs2tar/sqfs2tar.1 b/bin/sqfs2tar/sqfs2tar.1
index 0fc69f6..be79312 100644
--- a/bin/sqfs2tar/sqfs2tar.1
+++ b/bin/sqfs2tar/sqfs2tar.1
@@ -11,6 +11,13 @@ archives. The resulting archive is written to stdout.
.PP
Possible options:
.TP
+\fB\-\-compressor\fR, \fB\-c\fR <name>
+By default the result is a raw, uncompressed tar ball. Using this option
+it is possible to select a stream compression format (such as \fBgzip\fR,
+\fBxz\fR, \fBzstd\fR or \fBbzip2\fR) to use for the output archive.
+
+Run \fBsqfs2tar \-\-help\fR to get a list of all available compressors.
+.TP
\fB\-\-root\-becomes\fR, \fB\-r\fR <dir>
Prefix all paths in the tarball with the given directory name and add an
entry for this directory that receives all meta data (permissions, ownership,
@@ -69,18 +76,24 @@ Since the tar format contains a sequence of files with absolute names, it has
no direct concept of a tree or an unnamed root node. Consequently, meta data
from the SquashFS root inode is lost, unless the \fB\-\-root\-becomes\fR option
is used.
+
+The output archive can optionally be compressed. Default settings are used for
+the supported compressors and there is currently no intention to expose finer
+grained control over them. To set custom compressor flags, create an
+uncompressed archive and pipe it into a dedicated compressor process.
+
.SH EXAMPLES
Turn a SquashFS image into a tar archive:
.IP
sqfs2tar rootfs.sqfs > rootfs.tar
.TP
-Turn a SquashFS image into a gzip'ed tar archive:
+Creating a compressed archive with gzip headers:
.IP
-sqfs2tar rootfs.sqfs | gzip > rootfs.tar.gz
+sqfs2tar --compressor gzip rootfs.sqfs > rootfs.tar.gz
.TP
-Turn a SquashFS image into an LZMA2 compressed tar archive:
+Compressing the output archive, but using custom compressor flags:
.IP
-sqfs2tar rootfs.sqfs | xz > rootfs.tar.xz
+sqfs2tar rootfs.sqfs | xz -9e > rootfs.tar.xz
.SH SEE ALSO
rdsquashfs(1), tar2sqfs(1)
.SH AUTHOR