postlock - lock mail folder and execute command


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


   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.


   -c config_dir
          Read  the  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.


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

          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.


   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.


   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.


          Directory with Postfix configuration files.

          Enable verbose logging for debugging purposes.


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


   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

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


   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.


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


   postconf(5), configuration parameters


   The Secure Mailer license must be distributed with this software.


   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



Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.