diff --git a/cmdline.c b/cmdline.c
index 7203c3aa..7ea5cacc 100644
--- a/cmdline.c
+++ b/cmdline.c
@@ -563,7 +563,7 @@ int cmdline_process_param(const char *p, char *value,
     if (!strcmp(p, "-P")) {
         RETURN(2);
         UNAVAILABLE_IN(TOOLTYPE_NONNETWORK);
-        SAVEABLE(1);                   /* lower priority than -ssh,-telnet */
+        SAVEABLE(1);            /* lower priority than -ssh, -telnet, etc */
         conf_set_int(conf, CONF_port, atoi(value));
     }
     if (!strcmp(p, "-pw")) {
diff --git a/doc/gs.but b/doc/gs.but
index f7f7b1a2..a694e5b7 100644
--- a/doc/gs.but
+++ b/doc/gs.but
@@ -26,6 +26,7 @@ login sessions; you would usually use this for debugging other Internet
 services (see \k{using-rawprot}). The \e{Serial} option is used for
 connecting to a local serial line, and works somewhat differently:
 see \k{using-serial} for more information on this.
+\#{FIXME: describe bare ssh-connection}
 
 When you change the selected protocol, the number in the \q{Port}
 box will change. This is normal: it happens because the various
diff --git a/doc/index.but b/doc/index.but
index b2d1134d..78da4955 100644
--- a/doc/index.but
+++ b/doc/index.but
@@ -220,7 +220,9 @@ saved sessions from
 \IM{-telnet} \c{-telnet} command-line option
 \IM{-raw} \c{-raw} command-line option
 \IM{-rlogin} \c{-rlogin} command-line option
+\IM{-supdup} \c{-supdup} command-line option
 \IM{-ssh} \c{-ssh} command-line option
+\IM{-ssh-connection} \c{-ssh-connection} command-line option
 \IM{-serial} \c{-serial} command-line option
 \IM{-cleanup} \c{-cleanup} command-line option
 \IM{-load} \c{-load} command-line option
diff --git a/doc/man-putty.but b/doc/man-putty.but
index 02bba4ab..927dcf6b 100644
--- a/doc/man-putty.but
+++ b/doc/man-putty.but
@@ -184,7 +184,8 @@ in verifying new files released by the PuTTY team.
 straight from the command line without having to go through the
 configuration box first.
 
-\dt \cw{\-ssh}, \cw{\-telnet}, \cw{\-rlogin}, \cw{\-raw}, \cw{\-serial}
+\dt \cw{\-ssh}, \cw{\-telnet}, \cw{\-rlogin}, \cw{\-supdup}, \cw{\-raw},
+\cw{-ssh-connection}, \cw{\-serial}
 
 \dd Select the protocol \cw{putty} will use to make the connection.
 
diff --git a/doc/man-puttytel.but b/doc/man-puttytel.but
index 765c330d..bf852ddb 100644
--- a/doc/man-puttytel.but
+++ b/doc/man-puttytel.but
@@ -161,7 +161,7 @@ in verifying new files released by the PuTTY team.
 straight from the command line without having to go through the
 configuration box first.
 
-\dt \cw{\-telnet}, \cw{\-rlogin}, \cw{\-raw}
+\dt \cw{\-telnet}, \cw{\-rlogin}, \cw{\-supdup}, \cw{\-raw}
 
 \dd Select the protocol \cw{puttytel} will use to make the connection.
 
diff --git a/doc/plink.but b/doc/plink.but
index 9c98ef30..d4decf2d 100644
--- a/doc/plink.but
+++ b/doc/plink.but
@@ -51,6 +51,8 @@ use Plink:
 \c   -load sessname  Load settings from saved session
 \c   -ssh -telnet -rlogin -raw -serial
 \c             force use of a particular protocol
+\c   -ssh-connection
+\c             force use of the bare ssh-connection protocol
 \c   -P port   connect to specified port
 \c   -l user   connect with specified username
 \c   -batch    disable all interactive prompts
@@ -117,8 +119,8 @@ characters appearing in your window. Interactive connections like
 this are not the main point of Plink.
 
 In order to connect with a different protocol, you can give the
-command line options \c{-ssh}, \c{-telnet}, \c{-rlogin} or \c{-raw}.
-To make an SSH connection, for example:
+command line options \c{-ssh}, \c{-ssh-connection}, \c{-telnet},
+\c{-rlogin}, or \c{-raw}. To make an SSH connection, for example:
 
 \c C:\>plink -ssh login.example.com
 \c login as:
diff --git a/doc/using.but b/doc/using.but
index 577d4358..3fccf429 100644
--- a/doc/using.but
+++ b/doc/using.but
@@ -616,13 +616,13 @@ window}, or a \i{Windows shortcut}).
 
 \S{using-cmdline-session} Starting a session from the command line
 
-\I\c{-ssh}\I\c{-telnet}\I\c{-rlogin}\I\c{-raw}\I\c{-serial}These
+\I\c{-ssh}\I\c{-ssh-connection}\I\c{-telnet}\I\c{-rlogin}\I\c{-supdup}\I\c{-raw}\I\c{-serial}These
 options allow you to bypass the configuration window and launch
 straight into a session.
 
 To start a connection to a server called \c{host}:
 
-\c putty.exe [-ssh | -telnet | -rlogin | -raw] [user@]host
+\c putty.exe [-ssh | -ssh-connection | -telnet | -rlogin | -supdup | -raw] [user@]host
 
 If this syntax is used, settings are taken from the \i{Default Settings}
 (see \k{config-saving}); \c{user} overrides these settings if
@@ -688,23 +688,32 @@ must be the very first thing on the command line. This form of the
 option is deprecated.)
 
 \S2{using-cmdline-protocol} Selecting a protocol: \c{-ssh},
-\c{-telnet}, \c{-rlogin}, \c{-raw} \c{-serial}
+\c{-ssh-connection}, \c{-telnet}, \c{-rlogin}, \c{-supdup},
+\c{-raw}, \c{-serial}
 
 To choose which protocol you want to connect with, you can use one
 of these options:
 
 \b \i\c{-ssh} selects the SSH protocol.
 
+\b \i\c{-ssh-connection} selects the bare ssh-connection protocol.
+(This is only useful in specialised circumstances.)
+\#{FIXME: describe those circumstances somewhere in this manual,
+with reference to the psusan man page}
+
 \b \i\c{-telnet} selects the Telnet protocol.
 
 \b \i\c{-rlogin} selects the Rlogin protocol.
 
+\b \i\c{-supdup} selects the SUPDUP protocol.
+
 \b \i\c{-raw} selects the raw protocol.
 
 \b \i\c{-serial} selects a serial connection.
 
-These options are not available in the file transfer tools PSCP and
-PSFTP (which only work with the SSH protocol).
+Most of these options are not available in the file transfer tools
+PSCP and PSFTP (which only work with the SSH protocol and the bare
+ssh-connection protocol).
 
 These options are equivalent to the \i{protocol selection} buttons
 in the Session panel of the PuTTY configuration box (see
diff --git a/unix/uxplink.c b/unix/uxplink.c
index 0af98ec5..495a2b5d 100644
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -501,6 +501,8 @@ static void usage(void)
     printf("  -load sessname  Load settings from saved session\n");
     printf("  -ssh -telnet -rlogin -raw -serial\n");
     printf("            force use of a particular protocol\n");
+    printf("  -ssh-connection\n");
+    printf("            force use of the bare ssh-connection protocol\n");
     printf("  -P port   connect to specified port\n");
     printf("  -l user   connect with specified username\n");
     printf("  -batch    disable all interactive prompts\n");
diff --git a/windows/winplink.c b/windows/winplink.c
index 79fa5ab4..d589c22c 100644
--- a/windows/winplink.c
+++ b/windows/winplink.c
@@ -123,6 +123,8 @@ static void usage(void)
     printf("  -load sessname  Load settings from saved session\n");
     printf("  -ssh -telnet -rlogin -raw -serial\n");
     printf("            force use of a particular protocol\n");
+    printf("  -ssh-connection\n");
+    printf("            force use of the bare ssh-connection protocol\n");
     printf("  -P port   connect to specified port\n");
     printf("  -l user   connect with specified username\n");
     printf("  -batch    disable all interactive prompts\n");