diff --git a/doc/hook/modify_command_fname b/doc/hook/modify_command_fname
new file mode 100644
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+++ b/doc/hook/modify_command_fname
@@ -0,0 +1,44 @@
+SYNOPSIS
+        #include <sys/driver_hooks.h>
+
+        set_driver_hook(H_MODIFY_COMMAND_FNAME, value)
+
+        <value> being:
+
+          int|string <name>(string cmd)
+
+DESCRIPTION
+        Mandatory hook specifying the name of the 'modify_command'
+        lfun to call for newly entered commands as result of a
+        set_modify_command().
+
+        Hook setting must be a string.
+
+        If set_modify_command() is used for an interactive user, all
+        newly entered commands are first passed to the function named
+        by this hook.
+
+        The function is called with the command as argument.
+
+        If the result is a string, it is the new command to execute
+        instead of the given one. Note that it is not possible to make
+        several commands from one this way!
+
+        If the result is a non-zero number, the given command is to be
+        ignored. In case of the closure/lfun setting this may mean
+        that the closure/lfun already executed it.
+
+        If the result is 0, the originally given command is to be
+        used.
+
+        It is possible for the hook to change the command giver
+        (this_player()) for the execution of the command. This means
+        that even though the commands are execute for the original
+        commandgiver, this_player() will return the changed
+        commandgiver.
+
+HISTORY
+
+SEE ALSO
+        hooks(C), command(H), modify_command(H), notify_fail(H),
+        send_notify_fail(H)