(https://datatracker.ietf.org/doc/html/rfc5854)
.meta4-file for single specified file.
--fn NAME -- the only required option specifying file's name.
--desc "..." -- set file's description.
--mtime FILE -- let published date be equal to FILE's mtime.
--sig FILE -- path to armored OpenPGP's signature file.
--torrent URL -- set BitTorrent's URL.
+-fn NAME -- the only required option specifying file's name.
+-desc "..." -- set file's description.
+-mtime FILE -- let published date be equal to FILE's mtime.
+-sig-pgp .asc -- path to armored OpenPGP's signature file.
+-sig-ssh .sig -- path to armored OpenSSH's signature file.
+-torrent URL -- set BitTorrent's URL.
-hashes -- comma-separated list of colon-separated pairs of hash'es
name and the external command used to compute it. Command
shall take the data from stdin and print the digest in