diff --git a/doc/man-pl.but b/doc/man-pl.but
index 179a926a..abd4ff9b 100644
--- a/doc/man-pl.but
+++ b/doc/man-pl.but
@@ -267,6 +267,16 @@ an effort is made to suppress obvious passwords.)
 encrypted packet data.
 }
 
+\dt \cw{\-logoverwrite}
+
+\dd If Plink is configured to write to a log file that already exists,
+discard the existing file.
+
+\dt \cw{\-logappend}
+
+\dd If Plink is configured to write to a log file that already exists,
+append new log data to the existing file.
+
 \dt \cw{\-shareexists}
 
 \dd Instead of making a new connection, test for the presence of an
diff --git a/doc/man-pscp.but b/doc/man-pscp.but
index 515e541f..f06b02a6 100644
--- a/doc/man-pscp.but
+++ b/doc/man-pscp.but
@@ -176,6 +176,16 @@ to suppress obvious passwords.)
 encrypted packet data.
 }
 
+\dt \cw{\-logoverwrite}
+
+\dd If PSCP is configured to write to a log file that already exists,
+discard the existing file.
+
+\dt \cw{\-logappend}
+
+\dd If PSCP is configured to write to a log file that already exists,
+append new log data to the existing file.
+
 \S{pscp-manpage-more-information} MORE INFORMATION
 
 For more information on \cw{pscp} it's probably best to go and look at
diff --git a/doc/man-psft.but b/doc/man-psft.but
index c1329d0e..25cce3be 100644
--- a/doc/man-psft.but
+++ b/doc/man-psft.but
@@ -156,6 +156,16 @@ to suppress obvious passwords.)
 encrypted packet data.
 }
 
+\dt \cw{\-logoverwrite}
+
+\dd If PSFTP is configured to write to a log file that already exists,
+discard the existing file.
+
+\dt \cw{\-logappend}
+
+\dd If PSFTP is configured to write to a log file that already exists,
+append new log data to the existing file.
+
 \S{psftp-manpage-commands} COMMANDS
 
 For a list of commands available inside \cw{psftp}, type \cw{help}
diff --git a/doc/man-putt.but b/doc/man-putt.but
index 45dfd50f..cd8174bc 100644
--- a/doc/man-putt.but
+++ b/doc/man-putt.but
@@ -128,6 +128,16 @@ an effort is made to suppress obvious passwords.)
 encrypted packet data.
 }
 
+\dt \cw{\-logoverwrite}
+
+\dd If \cw{putty} is configured to write to a log file that already exists,
+discard the existing file.
+
+\dt \cw{\-logappend}
+
+\dd If \cw{putty} is configured to write to a log file that already exists,
+append new log data to the existing file.
+
 \dt \cw{\-cs} \e{charset}
 
 \dd This option specifies the character set in which \cw{putty}
diff --git a/doc/plink.but b/doc/plink.but
index ea622151..9c98ef30 100644
--- a/doc/plink.but
+++ b/doc/plink.but
@@ -90,6 +90,9 @@ use Plink:
 \c   -sshlog file
 \c   -sshrawlog file
 \c             log protocol details to a file
+\c   -logoverwrite
+\c   -logappend
+\c             control what happens when a log file already exists
 \c   -shareexists
 \c             test whether a connection-sharing upstream exists
 
diff --git a/doc/pscp.but b/doc/pscp.but
index c8585764..82d516c4 100644
--- a/doc/pscp.but
+++ b/doc/pscp.but
@@ -72,6 +72,9 @@ use PSCP:
 \c   -sshlog file
 \c   -sshrawlog file
 \c             log protocol details to a file
+\c   -logoverwrite
+\c   -logappend
+\c             control what happens when a log file already exists
 
 (PSCP's interface is much like the Unix \c{scp} command, if you're
 familiar with that.)
diff --git a/doc/using.but b/doc/using.but
index a56abc8b..9161db35 100644
--- a/doc/using.but
+++ b/doc/using.but
@@ -1025,7 +1025,7 @@ For example, \cq{-sercfg 19200,8,n,1,N} denotes a baud rate of
 19200, 8 data bits, no parity, 1 stop bit and no flow control.
 
 \S2{using-cmdline-sshlog} \i\c{-sessionlog}, \i\c{-sshlog},
-\i\c{-sshrawlog}: specify session logging
+\i\c{-sshrawlog}: enable session logging
 
 These options cause the PuTTY network tools to write out a \i{log
 file}. Each of them expects a file name as an argument, e.g.
@@ -1041,6 +1041,14 @@ different logging modes, all available from the GUI too:
 
 For more information on logging configuration, see \k{config-logging}.
 
+\S2{using-cmdline-logfileexists} \i\c{-logoverwrite}, \i\c{-logappend}:
+control behaviour with existing log file
+
+If logging has been enabled (in the saved configuration, or by another
+command-line option), and the specified log file already exists, these
+options tell the PuTTY network tools what to do so that they don't
+have to ask the user. See \k{config-logfileexists} for details.
+
 \S2{using-cmdline-proxycmd} \i\c{-proxycmd}: specify a local proxy
 command
 
diff --git a/pscp.c b/pscp.c
index 9827b7f4..b48608ce 100644
--- a/pscp.c
+++ b/pscp.c
@@ -2214,6 +2214,9 @@ static void usage(void)
     printf("  -sshlog file\n");
     printf("  -sshrawlog file\n");
     printf("            log protocol details to a file\n");
+    printf("  -logoverwrite\n");
+    printf("  -logappend\n");
+    printf("            control what happens when a log file already exists\n");
     cleanup_exit(1);
 }
 
diff --git a/psftp.c b/psftp.c
index 6bdf01e3..c1baa187 100644
--- a/psftp.c
+++ b/psftp.c
@@ -2546,6 +2546,9 @@ static void usage(void)
     printf("  -sshlog file\n");
     printf("  -sshrawlog file\n");
     printf("            log protocol details to a file\n");
+    printf("  -logoverwrite\n");
+    printf("  -logappend\n");
+    printf("            control what happens when a log file already exists\n");
     cleanup_exit(1);
 }
 
diff --git a/unix/uxplink.c b/unix/uxplink.c
index a23e4384..0c573bf8 100644
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -543,6 +543,9 @@ static void usage(void)
     printf("  -sshlog file\n");
     printf("  -sshrawlog file\n");
     printf("            log protocol details to a file\n");
+    printf("  -logoverwrite\n");
+    printf("  -logappend\n");
+    printf("            control what happens when a log file already exists\n");
     printf("  -shareexists\n");
     printf("            test whether a connection-sharing upstream exists\n");
     exit(1);
diff --git a/windows/winplink.c b/windows/winplink.c
index 83f988ad..f521861c 100644
--- a/windows/winplink.c
+++ b/windows/winplink.c
@@ -165,6 +165,9 @@ static void usage(void)
     printf("  -sshlog file\n");
     printf("  -sshrawlog file\n");
     printf("            log protocol details to a file\n");
+    printf("  -logoverwrite\n");
+    printf("  -logappend\n");
+    printf("            control what happens when a log file already exists\n");
     printf("  -shareexists\n");
     printf("            test whether a connection-sharing upstream exists\n");
     exit(1);