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QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
Utilities & Libraries
Utilities Reference
H
head (target)
Copy the first part of files (POSIX, toybox)

QNX Momentics IDE User's Guide
This User's Guide describes version 8.0 of the Integrated Development Environment (IDE) that's part of the QNX Tool Suite.
QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
- Quickstart Guide
- System Architecture
  The System Architecture guide accompanies the QNX OS and is intended for both application developers and end-users.
- OS Components & Operations
- Graphics
- Programming
- System Security Guide
  The QNX System Security Guide is intended for both system integrators who are responsible for the security of a QNX OS system and developers who want to create a QNX OS resource manager free from vulnerabilities.
- Utilities & Libraries
  - C Library Reference
  - Devctl and Ioctl Commands
  - JSON Library Reference
  - PAM Reference
  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SPI Framework Technote
  - QNX Cryptography Library
    The QNX Cryptography Library (qcrypto) is a flexible cryptography framework that allows you to choose which cryptography provider responds to requests on a per-process basis.
  - QNX devcrypto Service
  - Utilities Reference
    - Utility Conventions
    - A
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    - D
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    - F
    - G
    - H
      - ham
        High-availability manager
      - hamctrl
        Control a high-availability manager
      - hd (host)
        Display files in decimal, hex, octal, or ASCII (UNIX)
      - hd (target)
        Dump files in hexadecimal format (POSIX, toybox)
      - head (host)
        Copy the first part of files (POSIX)
      - head (target)
        Copy the first part of files (POSIX, toybox)
      - hexdump
        Dump files in hexadecimal format (POSIX, toybox)
      - hidview
        Display information about human-interface devices
      - hogs
        List the processes that are hogging the CPU
      - hostapd-version
        Daemon for access point and authentication servers
      - hostapd_cli-version
        Query the hostapd daemon from a command-line client
      - hostname
        Set or print the name of the current host system
      - /etc/hosts
        Hostname database (UNIX)
    - I
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    - Commonly Used Environment Variables
    - Selecting the Target System
    - Glossary
  - WPA Control Interface Reference
    This document provides a reference for the Wi-Fi Protected Access (WPA) control interface, which provides a C API for the WPA/IEEE 802.11i protocols in Wi-Fi client stations. Application developers who want to control WPA operations and get associated status and event data should read this reference.
- Migrating to QNX OS 8.0
QNX Software in the Cloud
QNX Software in the Cloud enables developers to use the QNX OS in the Amazon cloud environment.
QNX Toolkit for Visual Studio Code
This User's Guide describes the QNX^® Toolkit for Visual Studio Code. The guide introduces you to the QNX Toolkit by explaining the QNX development environment and how to build, run, and debug your QNX^® Operating System (OS) applications and systems.
QNX Hypervisor User's Guide
This User's Guide explains the QNX hypervisor architecture and provides instructions for installing and running a QNX Hypervisor system, changing system components and configuration, and using hypervisor features such as virtual devices (vdevs).
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation, explains how to obtain technical support, and provides some information about licensing.

head (target)

Copy the first part of files (POSIX, toybox)

Syntax:

head [-cn num] [-qv] [file...]

Runs on:

QNX OS

Options:

-c num: Number of bytes to copy.
-n num: Number of lines to copy.
-q: Never print file headers.
-v: Always print file headers.
file: The pathname of the input file that is copied to stdout.

Description:

The head utility copies its input files to the specified point of the standard output. If no files are listed, copy from stdin. The filename - is a synonym for stdin.

This utility is provided as part of the toybox package. For information on how to enable it, see toybox.

Contributing author:

Rob Landley and the toybox project (see https://landley.net/toybox/).

Page updated: August 11, 2025