-a <url>[,<url>]* : specify the full announce URLs
at least one is required
additional -a adds backup trackers
-c <comment> : add a comment to the metainfo
-d : don't write the creation date
-h : show this help screen
-l <n> : set the piece length to 2^n bytes,
default is 18, that is 2^18 = 256kb
-n <name> : set the name of the torrent,
default is the basename of the target
-o <filename> : set the path and filename of the created file
default is <name>.torrent
-p : set the private flag
-t <n> : use <n> threads for calculating hashes
default is 2
-v : be verbose
-w <url>[,<url>]* : add web seed URLs
additional -w adds more URLs