title: Check if a program is installed on a linux machine from a java applet
body: <p>Hi I need to be able to check if a certain software is installed on the clients computer  and where, in order to launch it. I found the following three posts as to how to do so on Windows and Mac but I can't seem to figure it out for Linux as there is no registry. Does any one know how this can be done on Linux?</p>
  
  <p>Similar posts for Windows and Mac:<br>
  <a href="https://stackoverflow.com/questions/4854775/can-a-java-applet-open-a-select-directory-and-write-to-a-filesystem-via-javascr">Can a Java applet open a &quot;select directory&quot; and write to a filesystem via JavaScript interaction?</a><br>
  <a href="https://stackoverflow.com/questions/62289/read-write-to-windows-registry-using-java">read/write to Windows Registry using Java</a> <br>
  <a href="https://stackoverflow.com/questions/4748895/how-can-i-see-the-software-installed-in-a-mac-os-using-a-java-application">How can I see the software installed in a Mac OS using a java application?</a></p>
  
  <p>any help would be greatly appreciated :)</p>