A very short one, but regularly asked by my mentees: how to copy the contents of a catalog? Just use IDCAMS’ REPRO facility, like you would for a regular VSAM dataset

//COPYCAT   EXEC PGM=IDCAMS                           
//SYSPRINT DD SYSOUT=*                         
//SYSIN    DD *                                      
REPRO  INDATASET(CATALOG.MVSICFM.VD9ECAT) -         
        OUTDATASET(SYS1.MSTRCTLG)    

//Pierre G