-Update the known_hosts file. For every host listed, search for a gpg
-key for the host in the Web of Trust. If a key is found, any ssh keys
-for the host are removed from the known_hosts file. If the found key
-is acceptable (see KEY ACCEPTABILITY), then the gpg key is converted
-to an ssh key and added to the known_hosts file. If now gpg key is
-found for the host, then nothing is done. If no hosts are specified,
-all hosts listed in the known_hosts file will be processed. If they
-`k' may be used in place of `update-known_hosts'.
+Update the known_hosts file. For each specified host, gpg will be
+queried for a key associated with the host URI (see HOST
+IDENTIFICATION in
+.BR monkeysphere(7)),
+optionally querying a keyserver.
+If an acceptable key is found for the host (see KEY ACCEPTABILITY in
+.BR monkeysphere(7)),
+the key is added to the user's known_hosts file. If a key is found
+but is unacceptable for the host, any matching keys are removed from
+the user's known_hosts file. If no gpg key is found for the host,
+nothing is done. If no hosts are specified, all hosts listed in the
+known_hosts file will be processed. This subcommand will exit with a
+status of 0 if at least one acceptable key was found for a specified
+host, 1 if no matching keys were found at all, and 2 if matching keys
+were found but none were acceptable. `k' may be used in place of
+`update-known_hosts'.
+.TP
+.B ssh-proxycommand
+an ssh proxy command that can be used
+to trigger a monkeysphere update of the ssh known_hosts file for a
+host that is being connected to with ssh. This works by updating the
+known_hosts file for the host first, before an attempted connection to
+the host is made. Once the known_hosts file has been updated, a TCP
+connection to the host is made by exec'ing netcat(1). Regular ssh
+communication is then done over this netcat TCP connection (see
+ProxyCommand in ssh_config(5) for more info).
+
+This command is meant to be run as the ssh "ProxyCommand". This can
+either be done by specifying the proxy command on the command line:
+
+.B ssh -o ProxyCommand="monkeysphere ssh-proxycommand %h %p" ...
+
+or by adding the following line to your ~/.ssh/config script:
+
+.B ProxyCommand monkeysphere ssh-proxycommand %h %p
+
+The script can easily be incorporated into other ProxyCommand scripts
+by calling it with the "--no-connect" option, i.e.:
+
+.B monkeysphere ssh-proxycommand --no-connect "$HOST" "$PORT"
+
+This will run everything except the final exec of netcat to make the
+TCP connection to the host. In this way this command can be added to
+another proxy command that does other stuff, and then makes the
+connection to the host itself.
+
+KEYSERVER CHECKING:
+The proxy command has a fairly nuanced policy for when keyservers are
+queried when processing a host. If the host userID is not found in
+either the user's keyring or in the known_hosts file, then the
+keyserver is queried for the host userID. If the host userID is found
+in the user's keyring, then the keyserver is not checked. This
+assumes that the keyring is kept up-to-date, in a cronjob or the like,
+so that revocations are properly handled. If the host userID is not
+found in the user's keyring, but the host is listed in the known_hosts
+file, then the keyserver is not checked. This last policy might
+change in the future, possibly by adding a deferred check, so that
+hosts that go from non-monkeysphere-enabled to monkeysphere-enabled
+will be properly checked.
+
+Setting the MONKEYSPHERE_CHECK_KEYSERVER
+variable (to `true' or `false') will override the keyserver-checking policy
+defined above.
+