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POSTLOCK(1) General Commands Manual POSTLOCK(1)

📛 NAME

postlock - lock mail folder and execute command

🚀 Quick Reference

Use Case	Command	Description
Lock mailbox and run command	postlock file command...	Locks file exclusively and executes command... (no shell interpreter)
Override lock style	postlock -l lock_style file command...	Uses specified lock_style instead of mailbox_delivery_lock parameter
Verbose debugging	postlock -v file command...	Enables verbose logging; multiple -v increase verbosity
Custom config directory	postlock -c config_dir file command...	Reads main.cf from config_dir

📋 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

📛 NAME 🚀 Quick Reference 📋 SYNOPSIS 🖋️ DESCRIPTION 🩺 DIAGNOSTICS 🐛 BUGS 🌿 ENVIRONMENT ⚙️ CONFIGURATION PARAMETERS 📚 SEE ALSO 📄 LICENSE 👤 AUTHOR(S)