lockfile-progs(1) Lockfile programs lockfile-progs(1) NAME lockfile-progs - command-line programs to safely lock and unlock files and mailboxes (via liblockfile). SYNOPSIS mail-lock [--use-pid] [--retry retry-count] mail-unlock mail-touchlock [--oneshot] lockfile-create [--use-pid] [--retry retry-count] [--lock-name] filename lockfile-remove [--lock-name] filename lockfile-touch [--oneshot] [--lock-name] filename lockfile-check [--use-pid] [--lock-name] filename DESCRIPTION Lockfile-progs provides a set a programs that can be used to lock and unlock mailboxes and files safely (via liblockfile): mail-lock - lock the current user's mailbox mail-unlock - unlock the current user's mailbox mail-touchlock - touch the lock on the current user's mailbox lockfile-create - lock a given file lockfile-remove - remove the lock on a given file lockfile-touch - touch the lock on a given file lockfile-check - check the lock on a given file By default, the filename argument refers to the name of the file to be locked, and the name of the lockfile will be filename .lock. However, if the --lock-name argument is specified, then filename will be taken as the name of the lockfile itself. Each of the mail locking commands attempts to lock /var/spool/mail/<user>, where <user> is the name associated with the effective user ID, as determined by via geteuid(2). Once a file is locked, the lock must be touched at least once every five minutes or the lock will be considered stale, and subsequent lock attempts will succeed. Also see the --use-pid option and the lock- file_create(3) manpage. The lockfile-check command tests whether or not a valid lock already exists. OPTIONS -q, --quiet Suppress any output. Success or failure will only be indicated by the exit status. -v, --verbose Enable diagnostic output. -l, --lock-name Do not append .lock to the filename. This option applies to lock- file-create, lockfile-remove, lockfile-touch, or lockfile-check. -p, --use-pid Write the current process id (PID) to the lockfile whenever a lock- file is created, and use that pid when checking a lock's validity. See the lockfile_create(3) manpage for more information. This option applies to lockfile-create, lockfile-remove, lockfile-touch, and lockfile-check. -o, --oneshot Touch the lock and exit immediately. This option applies to lock- file-touch and mail-touchlock. When not provided, these commands will run forever, touching the lock once every minute until killed. -r retry-count, --retry-count retry-count Try to lock filename retry-count times before giving up. Each attempt will be delayed a bit longer than the last (in 5 second increments) until reaching a maximum delay of one minute between retries. If retry-count is unspecified, the default is 9 which will give up after 180 seconds (3 minutes) if all 9 lock attempts fail. EXAMPLES Locking a file during a lengthy process: lockfile-create /some/file lockfile-touch /some/file & # Save the PID of the lockfile-touch process BADGER="$!" do-something-important-with /some/file kill "${BADGER}" lockfile-remove /some/file EXIT STATUS 0 For lockfile-check this indicates that a valid lock exists, other- wise it just indicates successful program execution. Not 0 For lockfile-check a non-zero exit status indicates that the speci- fied lock does not exist or is not valid. For other programs it indicates that some problem was encountered. SEE ALSO maillock(3) touchlock(3) mailunlock(3) lockfile_create(3) lockfile_remove(3) lockfile_touch(3) lockfile_check(3) AUTHOR Written by Rob Browning <rlb@defaultvalue.org> 0.1.12 2008-02-10 lockfile-progs(1)