addr1 addr2 addr3 addr1,addr2,addr3 addr1, addr2, addr3
Certain modes specified by the
-b command-line switch,
-bp (for print the queue's contents), cause sendmail
to ignore any list of recipients.
Be sure to escape any characters in addresses that
have special meaning to your shell. For example, because the
character has special meaning to the C-shell,
it should be escaped by preceding it with a backslash character:
 And its derivatives such as tcsh(1).
If sendmail expects a list of recipients and finds none, it prints the following message and exits:
Recipient names must be specified