The clipper command to copy any single file is "copy file"
Assuming that drives C:& D:, folders (1 & 2) and file a.dbf already exist, the following line will copy file a.dbf from folder 1 on c: drive to folder 2 on d: drive and rename it to b.dbf in the process:
COPY FILE "c:\1\a.dbf" TO "d:\2\b.dbf