systemd-vpick — Resolve paths to ".v/" versioned directories
systemd-vpick [OPTIONS...] [PATH...]
systemd-vpick resolves a file system path referencing a ".v/"
versioned directory to a path to the newest (by version) file contained therein. This tool provides a
command line interface for the
systemd.v(7)
logic.
The tool expects a path to a ".v/" directory as argument (either directly, or with
a triple underscore pattern as final component). It then determines the newest file contained in that
directory, and writes its path to standard output.
Unless the triple underscore pattern is passed as last component of the path, it is typically
necessary to at least specify the --suffix= switch to configure the file suffix to look
for.
If the specified path does not reference a ".v/" path (i.e. neither the final
component ends in ".v", nor the penultimate does or the final one does contain a triple
underscore) it specified path is written unmodified to standard output.
The following options are understood:
--basename=, -B¶Overrides the "basename" of the files to look for, i.e. the part to the left of the
variable part of the filenames. Normally this is derived automatically from the filename of the
".v" component of the specified path, or from the triple underscore pattern in the
last component of the specified path.
-V¶Explicitly configures the version to select. If specified, a filename with the specified version string will be looked for, instead of the newest version available.
-A¶Explicitly configures the architecture to select. If specified, a filename with the specified architecture identifier will be looked for. If not specified only filenames with a locally supported architecture are considered, or those without any architecture identifier.
--suffix=, -S¶Configures the suffix of the filenames to consider. For the ".v/"
logic it is necessary to specify the suffix to look for, and the ".v/" component
must also carry the suffix immediately before ".v" in its name.
--type=, -t¶Configures the inode type to look for in the ".v/" directory. Takes
one of "reg", "dir", "sock",
"fifo", "blk", "chr", "lnk" as
argument, each identifying an inode type. See inode(7) for
details about inode types. If this option is used inodes not matching the specified type are filtered
and not taken into consideration.
--print=, -p¶Configures what precisely to write to standard output. If not specified prints the
full, resolved path of the newest matching file in the ".v/" directory. This switch can be set to one of the following:
If set to "filename", will print only the filename instead of the full path of the resolved file.
If set to "version", will print only the version of the resolved file.
If set to "type", will print only the inode type of the resolved
file (i.e. a string such as "reg" for regular files, or "dir" for
directories).
If set to "arch", will print only the architecture of the resolved
file.
If set to "tries", will print only the tries left/tries done of the
resolved file.
If set to "all", will print all of the above in a simple tabular
output.
--resolve=¶Takes a boolean argument. If true the path to the versioned file is fully canonicalized (i.e. symlinks resolved, and redundant path components removed) before it is shown. If false (the default) this is not done, and the path is shown without canonicalization.
-h, --help¶--version¶Use a command like the following to automatically pick the newest raw disk image from a
".v/" directory:
$ systemd-vpick --suffix=.raw --type=reg /var/lib/machines/quux.raw.v/
This will enumerate all regular files matching
/var/lib/machines/quux.raw.v/quux*.raw, filter and sort them according to the rules
described in
systemd.v(7), and then
write the path to the newest (by version) file to standard output.
Use a command like the following to automatically pick the newest OS directory tree from a
".v/" directory:
$ systemd-vpick --type=dir /var/lib/machines/waldo.v/
This will enumerate all directory inodes matching
/var/lib/machines/waldo.v/waldo*, filter and sort them according to the rules
described in
systemd.v(7), and then
write the path to the newest (by version) directory to standard output.
For further examples see systemd.v(7).