lock user's system mailbox
is useful for a client mail program
to attain proper locking.
for the calling user and
retains it until stdin is closed or a signal like
is received. Additionally, the
superuser may specify the name of a user in order to lock a different mailbox.
is able to create the lock file,
“1” is written to stdout, otherwise “0” is written
and an error message is written to stderr.
will try up to 10 times to get
the lock (sleeping for a short period in between tries).
Typical usage is for a user mail agent (such as
) to open a pipe to
when it needs to lock the user's
mail spool. Closing the pipe will cause
to release the lock.
- user's mail lock file
utility exits 0 on success, and
1 if an error occurs.
program appeared in