vjs@calcite.UUCP (Vernon Schryver) (08/28/89)
There is a trouble with schemes for comparing mtime & atime to see if new
mail has arrived.
Atime>=mtime after /bin/mail has delivered mail, unless it cannot read the
mail box. Thus, since /bin/mail is SGID=mail to write it, you have to make
/usr/mail/$USER unreadable by group. Note that breaks /bin/mail's
forwarding mechanism.
If you use the bit of dung called mailx to look at mail, and delete some
but not all of the contents of your mailbox, mailx will carefully restore
atime<mtime. The stupidity is reasonably obvious in the source.
These bugs are in SVR3.[012]. Perhaps they are absent in Xenix.
Vernon Schryver
vjs@calcite.uucp or {pyramid,sgi}!calcite!vjs