I think Adam was asking how to change umask value for all processes that tying to operate on /opt/lampp/htdocs directory.
The user file-creation mode mask (umask) is use to determine the file permission for newly created files. It can be used to control the default file permission for new files.
so if you will use some kind of ftp program to upload files into /opt/lampp/htdocs you need to configure your ftp server to use umask you want.
If files / directories be created for example by php, you need to modify php code 
<?php
umask(0022);
// other code
?>
if you will create new files / folders from your bash session, you can set umask value in your shell profile ~/.bashrc 
Or you can set up umask in /etc/bashrc or /etc/profile file for all users.
add the following to file:
umask 022
Sample umask Values and File Creation Permissions
If umask value set to   User permission     Group permission     Others permission
000                         all              all                   all
007                         all              all                   none
027                         all          read / execute            none
And to change permissions for already created files you can use find.
Hope this helps.
 
				
chmod 75 /opt/lampp/htdocsor should that really bechmod 755 /opt/lampp/htdocs? - HelloGoodbye