Pos: Remove non-functional cdf command

Closes Homebrew#7799.

Signed-off-by: Charlie Sharpsteen <source@sharpsteen.net>

Library/Formula/pos.rb

@@ -5,15 +5,19 @@ class Pos < Formula
   md5 'c667fb4ca38c96494f888ade9fb4e40a'
   homepage "http://sage.ucsc.edu/~wgscott/xtal/wiki/index.php/Unix_and_OS_X:_The_Absolute_Essentials"
 
-  def cdf_script; <<-END
-#!/bin/bash
-cd "$(posd)"
-END
-  end
-
   def install
     bin.install %w[bin/fdc bin/posd]
-    (bin+'cdf').write cdf_script
     share.install %w[Finder_Toolbar_Applications.dmg.gz iTerm.webloc]
   end
+
+  def caveats
+      <<-EOS.undent
+      cdf (change terminal window to current finder window)
+      needs to be installed as an alias in your shell init.
+      For example, add the following to your .bash_profile:
+        if [ -f `brew --prefix`/bin/posd ]; then
+          alias cdf='cd "`posd`"'
+        fi
+      EOS
+  end
 end