Rewrite only a specific file using MOD_REWRITE

I have a file that can be reached using multiple paths:

http://mydomain.com/portal1/movie.swf
http://mydomain.com/portal2/movie.swf
http://mydomain.com/portal1/substep/movie.swf
etc.

I want a rewrite rule to get this specific file from the following path:

http://mydomain.com/movie.swf

How can I do that?

From stackoverflow

• in .htaccess in your main folder:

  RewriteRule ^portal.*movie\.swf$ /movie.swf [L]
  

  (backlash before the dot added after Gumbos comment. +1)

  Scharrels : I don't want to specify a rule for every possible path. Can I rewrite alle movie.swf's to /movie.swf using 1 rule?

  Scharrels : Never mind - your solution worked. I used RewriteRule ^.*/movie.swf$ /movie.swf [L]

  Gumbo : Don’t forget to escape the `.` character.