Use the Save Changed Objects (SAVCHGOBJ) command to save only those objects that have changed since a specified time.
The options for specifying objects, object types, and libraries are similar to those for the SAVOBJ command:
- You can specify up to 300 different libraries by using the LIB parameter. You may use specific or generic values.
- You can omit up to 300 libraries by using the OMITLIB parameter. You may specify generic values for this parameter.
- You can omit up to 300 objects by using the OMITOBJ parameter. You may specify generic values for this parameter.
Note: 
Use the Command user space (CMDUSRSPC) parameter on
the save commands to specify up to 32767 names for the parameters.
Use the Command user space (CMDUSRSPC) parameter on
the save commands to specify up to 32767 names for the parameters.You
can perform multiple concurrent SAVCHGOBJ operations against
a single library. This can be helpful if you need to save different parts
of a library to different media devices simultaneously, as shown in the following
example:
SAVCHGOBJ OBJ(A* B* C* $* #* @* ...L*) DEV(media-device-name-one) LIB(library-name) SAVCHGOBJ OBJ(M* N* O* ...Z*) DEV(media-device-name-two) LIB(library-name)