Before you begin: You need to know which superusers you want to change from UID(0) to a unique nonzero UID.

Perform the following steps to change a superuser from a UID of 0 to a unique nonzero UID.

1. Change the UID for the superuser from 0 to a unique UID. Base your choice on your particular situation.
   Choices for changing superusers

   If you choose this method . . .	Then . . .
   Have RACF® automatically assign an unused UID.	Delete the UID from the user's OMVS segment. For example: ALTUSER JOHN OMVS(NOUID) Issue the ALTUSER command with the AUTOUID keyword. For example: ALTUSER JOHN OMVS(AUTOUID) Message IRR52177I identifies the new UID.
   Use the ISPF shell to assign the next available UID.	Delete the UID from the user's OMVS segment. For example: ALTUSER JOHN OMVS(NOUID) Assign a new UID, using the ISPF shell. Tip: You can display the user's OMVS segment to see the UID that was assigned by the ISHELL. For example: LISTUSER JOHN OMVS
   Manually assign the UID. If the installation manually manages the UIDs assigned to users, select the next available UID and assign it to the user. Tip: To make sure the UID you selected is not already in use by another user, issue: SEARCH CLASS(USER) UID(7)	Use the ALTUSER command. Example: Assume that the next available UID is 7 and the user ID is JOHN. To reassign the UID, issue: ALTUSER JOHN OMVS(UID(7))

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2. Permit the user to the BPX.SUPERUSER resource in the FACILITY class.
   Example: For user ID John:

   PERMIT BPX.SUPERUSER CLASS(FACILITY) ID(JOHN) ACCESS(READ)

   Tip: You can choose to RACLIST the FACILITY class afterward. This step is optional. If you do so, then you will have to do a REFRESH after the user ID is permitted to the FACILITY class. For example:

   SETROPTS RACLIST(FACILITY) REFRESH

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3. Change the ownership of the user's private files to the new UID. These files are typically those defined in the home directory.
   Example: The home directory is /u/john. Issue the following command to update the ownership of the files.

   cd /u/john
   chown -R john /u/john

   Result: The owning UID of the /u/john directory is changed to 7. The owning UID of all files and subdirectories of the /u/john directory is also changed.

   Tip: The chown command requires a UID of 0, the ability to su to 0, or authority to SUPERUSER.FILESYS.CHOWN.

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When you are done, you have changed the superuser from a UID of 0 to a unique nonzero UID.