Use the "collate" option to enable print collation (which is disabled by default):
lp -n num-copies -o Collate=True filename
Source (CUPS documentation)
Print many copies of a pdf without using a for-loop?
Use the "collate" option to enable print collation (which is disabled by default):
lp -n num-copies -o Collate=True filename
Source (CUPS documentation)