setmaillist writes the mailing list in a binary format to tmp; it then moves tmp to bin. tmp and bin must be on the same filesystem.
If there is a problem creating tmp, setmaillist complains and leaves bin alone.
The binary mailing list format is portable across machines.
setmaillist always creates bin world-readable.
If a line begins with a dot or slash, setmaillist takes the entire line as an include file name.
If a line begins with an ampersand, setmaillist takes the rest of the line as a recipient address. If a line begins with a letter or number, setmaillist takes the entire line as a recipient address. Each recipient address must include a fully qualified domain name. Recipient addresses longer than 800 bytes are not allowed.
setmaillist ignores blank lines and lines beginning with #. It also ignores spaces and tabs at the ends of lines.
For example,
god@heaven.af.mil
djb@silverton.berkeley.edu
is a mailing list with two addresses.