lockmail — create mail lock files
lockmail [-r] [-t timeout] {lockfile} {program} [argument...]
lockmail is a helper utility for working with mailbox files. Mailbox files must be locked to prevent other applications from modifying the mailbox at the same time. Different system use different locking conventions. lockmail uses two of the most common locking mechanisms in use, which should work reliably on most systems.
lockfile is the pathname to an existing mailbox
file.
By default, lockmail tries to lock the mailbox every
five seconds (if the mailbox is already locked), and will give up after
three minutes.
After the mailbox is successfully locked, lockmail runs
program as a child process, with any optional
arguments.
When program terminates, lockmail
removes the mailbox lock, and terminates itself.
If a regular lock fails, try a read-only lock. Use this option to lock mailbox files in a read-only directory.
timeout
If the lock attempt fails, try again for up to
timeout seconds.
The actual timeout is rounded up to the next five second interval
(a lock attempt is tried every five seconds).