File Extension UX File Format Unix file UX stands for Unix file. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Comparing Unix versions: AIX, HP-UX and Solaris Analyst group touts Unix OS scorecard How do I convert a Unix text file from IFS to a DB file on AS400?