# man > POSTLOCK(1)

[POSTLOCK(1)](https://www.chedong.com/phpMan.php/man/POSTLOCK/1/markdown)                            General Commands Manual                           [POSTLOCK(1)](https://www.chedong.com/phpMan.php/man/POSTLOCK/1/markdown)



## NAME
       postlock - lock mail folder and execute command

## SYNOPSIS
       **postlock** [**-c** _config_dir_] [**-l** _lock_style_]
               [**-v**] _file_ _command..._

## DESCRIPTION
       The  [**postlock**(1)](https://www.chedong.com/phpMan.php/man/postlock/1/markdown)  command  locks _file_ for exclusive access, and executes _command_. The locking
       method is compatible with the Postfix UNIX-style local delivery agent.

       Options:

### -c
              Read the **main.cf** configuration file in the named directory instead of the default con‐
              figuration directory.

### -l
              Override  the locking method specified via the **mailbox**___**delivery**___**lock** configuration pa‐
              rameter (see below).

### -v -v
              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 exe‐
              cuted directly, i.e. without interpretation by a shell command interpreter.

## DIAGNOSTICS
       The result status is 75 (EX_TEMPFAIL) when [**postlock**(1)](https://www.chedong.com/phpMan.php/man/postlock/1/markdown) could not perform the requested opera‐
       tion.  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)](https://www.chedong.com/phpMan.php/man/postconf/5/markdown) 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)](https://www.chedong.com/phpMan.php/man/bounce/8/markdown) logfile.

       **deliver**___**lock**___**delay** **(1s)**
              The time between attempts to acquire an exclusive lock on a mailbox file or  [**bounce**(8)](https://www.chedong.com/phpMan.php/man/bounce/8/markdown)
              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)](https://www.chedong.com/phpMan.php/man/local/8/markdown) 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)](https://www.chedong.com/phpMan.php/man/postconf/5/markdown), 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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