ipcs

Updated

July 31, 2026

Overview

ipcs provides information on System V Inter-Process Communication (IPC) facilities: shared memory segments, message queues, and semaphore arrays.

Syntax

ipcs [options]

Common Options

Option Description
-a, --all Show all IPC facilities (default)
-m, --shmems Display shared memory segments
-q, --queues Display message queues
-s, --semaphores Display semaphore arrays
-p, --pid Display process IDs of IPC creators and last operators
-t, --time Display access/change timestamps

Key Use Cases

  1. Auditing active System V shared memory segments and semaphores.
  2. Identifying orphaned shared memory allocations.
  3. Troubleshooting database or multi-process IPC resource leaks.

Examples with Explanations

Example 1: View Shared Memory Segments

ipcs -m

Lists active shared memory segment IDs, keys, owners, permissions, and byte sizes.