Bennett Todd suggested for Era Eriksson's description of folders,
|"A folder is a data structure for holding email messages. There are many
| different mail folder formats. One widely-used format is called "mbox"
| format; this is a single file, containing one or more messages
| concatenated; each message begins with a line starting "From "
... and ends with two newlines.
| Another
| popular folder format is MH, in which the folder is a directory, and each
| message is a separate file; the filenames are the message numbers. Another
| popular folder format is Maildir; a Maildir folder is a directory, with
| three subdirectories named "tmp", "new", and "cur". Messages are written
| into "tmp", then moved to "new" to commit the delivery. As messages are
| read, they're moved from "new" to "cur", and renamed to append flags for
| the message status. In Maildir folders the files have long, complex names
| intended to ensure that all filenames are unique. Maildir is the only mail
| folder format that requires no locking."
The last statement is incorrect. Deliveries to ordinary directories or to
MH-style directories do not require locking either, because procmail picks a
unique filename for each message.
Era had asked,
| > (Somewhere in the FAQ, I would like to have instructions for figuring out
| > your MX host(s), too.)
Bennett replied,
| For modern Unixes:
|
| host -t mx `hostname`
|
| For older ones:
|
| (echo set q=mx;hostname)|nslookup
nslookup -q=mx `hostname`
should do the job.