Use the /NUMREC=record-number argument to limit the number of records that are to be imported from VSAM files.
Example:
The following command imports an ESDS data set but only downloads the first record:
MFDAS IMPORT "<catalogfolder>\data\*.*" FROM AUTO MFI01.TESTDC.ESDS /CATLOC=c:\proj\catalog.dat /NUMREC=1
Executing this command results in the following file being imported: