mongooplog arguments are unclearly documented, some irrelevant?

$ mongooplog --help

Pull and replay a remote MongoDB oplog.

options:

  --help                          produce help message

  -v [ --verbose ]                be more verbose (include multiple times for 

                                  more verbosity e.g. -vvvvv)

  --version                       print the program's version and exit

  -h [ --host ] arg               mongo host to connect to ( <set name>/s1,s2 

                                  for sets)

  --port arg                      server port. Can also use --host 

                                  hostname:port

  --ipv6                          enable IPv6 support (disabled by default)

  -u [ --username ] arg           username

  -p [ --password ] arg           password

  --dbpath arg                    directly access mongod database files in the 

                                  given path, instead of connecting to a mongod

                                    server - needs to lock the data directory, 

                                  so cannot be used if a mongod is currently 

                                  accessing the same path

  --directoryperdb                if dbpath specified, each db is in a separate

                                  directory

  --journal                       enable journaling

  -d [ --db ] arg                 database to use

  -c [ --collection ] arg         collection to use (some commands)

  -f [ --fields ] arg             comma separated list of field names e.g. -f 

                                  name,age

  --fieldFile arg                 file with fields names - 1 per line

  -s [ --seconds ] arg            seconds to go back default:86400

  --from arg                      host to pull from

  --oplogns arg (=local.oplog.rs) ns to pull from