Updated: 2022/Sep/29

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POSTLOCK(1)                 General Commands Manual                POSTLOCK(1)




NAME
       postlock - lock mail folder and execute command

SYNOPSIS
       postlock [-c config_dir] [-l lock_style]
               [-v] file command...

DESCRIPTION
       The postlock(1) command locks file for exclusive access, and executes
       command. The locking method is compatible with the Postfix UNIX-style
       local delivery agent.

       Options:

       -c config_dir
              Read the main.cf configuration file in the named directory
              instead of the default configuration directory.

       -l lock_style
              Override the locking method specified via the
              mailbox_delivery_lock configuration parameter (see below).

       -v     Enable verbose logging for debugging purposes. Multiple -v
              options make the software increasingly verbose.

       Arguments:

       file   A mailbox file. The user should have read/write permission.

       command...
              The command to execute while file is locked for exclusive
              access.  The command is executed directly, i.e. without
              interpretation by a shell command interpreter.

DIAGNOSTICS
       The result status is 75 (EX_TEMPFAIL) when postlock(1) could not
       perform the requested operation.  Otherwise, the exit status is the
       exit status from the command.

BUGS
       With remote file systems, the ability to acquire a lock does not
       necessarily eliminate access conflicts. Avoid file access by processes
       running on different machines.

ENVIRONMENT

       MAIL_CONFIG
              Directory with Postfix configuration files.

       MAIL_VERBOSE
              Enable verbose logging for debugging purposes.

CONFIGURATION PARAMETERS
       The following main.cf parameters are especially relevant to this
       program.  The text below provides only a parameter summary. See
       postconf(5) for more details including examples.

LOCKING CONTROLS

       deliver_lock_attempts (20)
              The maximal number of attempts to acquire an exclusive lock on a
              mailbox file or bounce(8) logfile.

       deliver_lock_delay (1s)
              The time between attempts to acquire an exclusive lock on a
              mailbox file or bounce(8) logfile.

       stale_lock_time (500s)
              The time after which a stale exclusive mailbox lockfile is
              removed.

       mailbox_delivery_lock (see 'postconf -d' output)
              How to lock a UNIX-style local(8) mailbox before attempting
              delivery.

RESOURCE AND RATE CONTROLS

       fork_attempts (5)
              The maximal number of attempts to fork() a child process.

       fork_delay (1s)
              The delay between attempts to fork() a child process.

MISCELLANEOUS CONTROLS

       config_directory (see 'postconf -d' output)
              The default location of the Postfix main.cf and master.cf
              configuration files.

       import_environment (see 'postconf -d' output)
              The list of environment parameters that a privileged Postfix
              process will import from a non-Postfix parent process, or
              name=value environment overrides.

SEE ALSO
       postconf(5), configuration parameters

LICENSE
       The Secure Mailer license must be distributed with this software.

AUTHOR(S)
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA



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