## 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:

\fB-c \fIconfig_dir\fR

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

\fB-l \fIlock_style\fR

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

\fB-v\fR

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

Arguments:

\fIfile\fR

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

\fIcommand...\fR

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

\fBMAIL_CONFIG\fR

Directory with Postfix configuration files.

\fBMAIL_VERBOSE\fR

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

\fBdeliver_lock_attempts (20)\fR

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

\fBdeliver_lock_delay (1s)\fR

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

\fBstale_lock_time (500s)\fR

The time after which a stale exclusive mailbox lockfile is removed.

\fBmailbox_delivery_lock (see 'postconf -d' output)\fR

How to lock a UNIX-style local(8) mailbox before attempting delivery.

## RESOURCE AND RATE CONTROLS

\fBfork_attempts (5)\fR

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

\fBfork_delay (1s)\fR

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

## MISCELLANEOUS CONTROLS

\fBconfig_directory (see 'postconf -d' output)\fR

The default location of the Postfix main.cf and master.cf configuration files.

## 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