document --with-askpass

diff --git a/INSTALL b/INSTALL
index 15a34c87f98ac6ebbd5cb380e3cc40e44b8fabcb..950b15fd458cc8979f3f331c695f4b7d28c6bc2a 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -528,6 +528,13 @@ The following options are also configurable at runtime:
        option.  visudo will then only use the VISUAL or EDITOR variables
        if they match a value specified via --with-editor.
 
+  --with-askpass=PATH
+        Set PATH as the "askpass" program to use when no tty is
+        available.  Typically, this is a graphical password prompter,
+        similar to the one used by ssh.  The program must take a
+        prompt as an argument and print the received password to
+        the standard output.
+
   --disable-authentication
        By default, sudo requires the user to authenticate via a
        password or similar means.  This options causes sudo to