add pass idea

TODO

@@ -19,3 +19,25 @@ Check is_utf8 license.
 
 c++ destructor double free mess
 
+Idea from encfs:
+       --extpass=program
+           Specify an external program to use for getting the user password.  When the external program
+           is spawned, the environment variable "RootDir" will be set to contain the path to the root
+           directory.  The program should print the password to standard output.
+
+           EncFS takes everything returned from the program to be the password, except for a trailing
+           newline (\n) which will be removed.
+
+           For example, specifying --extpass=/usr/lib/ssh/ssh-askpass will cause EncFS to use ssh's
+           password prompt program.
+
+           Note: EncFS reads at most 2k of data from the password program, and it removes any trailing
+           newline.  Versions before 1.4.x accepted only 64 bytes of text.
+
+       -S, --stdinpass
+           Read password from standard input, without prompting.  This may be useful for scripting encfs
+           mounts.
+
+           Note that you should make sure the filesystem and mount points exist first.  Otherwise encfs
+           will prompt for the filesystem creation options, which may interfere with your script.
+