Sometimes it is needed to change files on the USS partition to customize them. Like the profile file, or the server.xml. To do this you can use the VI or ED commands in USS itself.
But they are very user unfriendly. How to prevent the usage of VI and ED.
In TSO PDF there is the option 3 (Utilities) and on this Utility panel you have option 17: Udlist. It can print or display z/OS UNIX directory lists. To display the file you can enter the 'E' (edit) command line, but when it's ASCII, you will only see 'garbage' on your screen. If you issue the 'EA' line command, then you will see the text in EBCDIC instead of ASCII. (EA: Edit a ASCII file)