Use the ATTRIB command to build a list of attributes for non-VSAM data sets that you intend to allocate dynamically. During the remainder of your terminal session, you can have the system this list for data set attributes when you enter the ALLOCATE command. The ALLOCATE command converts the attributes into DCB operands and LABEL operands for data sets being allocated. See the subparameters of the DCB parameter in z/OS MVS JCL Reference.

The ATTRIB command allocates a file with the same name as your attr_list_name. You can use the LISTALC command with the STATUS operand to list your active attribute lists. The data set name is NULLFILE, which is also the data set name for files allocated with the DUMMY operand of the ALLOCATE command. Because this is a NULLFILE allocation, it is subject to use and modification by other commands. Therefore, it is advisable to allocate those data sets for which the attribute list was built before you issue any commands that might cause NULLFILE allocation, such as LINK or RUN.

With the LIKE operand and the DCB operands on the ALLOCATE command, you do not have to use the ATTRIB command.