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QNX Software Development Platform
OS Components
User's Guide
The QNX OS User's Guide is intended for all users of a QNX OS system, from system administrators to end users.
Using the Command Line
Like QNX 4, Unix, and DOS, the QNX OS is based on a command-line interface that you might want or need to use instead of the GUI.
Shell
After the character-device driver processes what you type, the command line is passed to a command interpreter or shell.
History: recalling commands
The shell lets you recall commands that you've previously entered; use the up and down arrow keys to move through the history buffer. You can edit the command, if you wish, and then press Enter to reexecute it.

QNX Momentics IDE User's Guide
QNX Software Development Platform
- Quickstart Guide
- System Architecture
  The System Architecture guide accompanies the QNX OS and is intended for both application developers and end-users.
- OS Components
  - Boot Optimization Guide
    The Boot Optimization Guide describes techniques you can use to reduce the time from your board's initial power on until you have a fully functional QNX system running on the board.
  - Building Embedded Systems
    The Building Embedded Systems guide is intended for developers who are developing or building BSPs for QNX OS embedded systems.
  - Customizing a BSP
    While QNX provides Board Support Packages (BSPs) for many common platforms and their individual variants, in some cases, you need a BSP for a board that QNX does not provide. If this is the case, you can modify a QNX BSP or develop your own.
  - High Availability Framework Developer's Guide
  - High-Performance Networking Stack (io-sock) User's Guide
    This guide contains instructions for implementing and using the QNX OS High-Performance Networking Stack and its manager, io-sock.
  - PCI Server User's Guide
  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SMMUMAN User's Guide
  - SPI Framework Technote
  - System Analysis Toolkit (SAT) User's Guide
  - Technotes
  - User's Guide
    The QNX OS User's Guide is intended for all users of a QNX OS system, from system administrators to end users.
    - Getting to Know the OS
      Welcome to the QNX OS!
    - Logging In, Logging Out, and Shutting Down
      QNX OS is a multiuser operating system; it lets multiple users log in and use the system simultaneously, and it protects them from each other through a system of resource ownership and permissions.
    - Managing User Accounts
      This chapter explains how user accounts work, how users can change their password by using the passwd utility, and how system administrators can use the passwd utility and edit account database files to create and maintain users' accounts.
    - Using the Command Line
      Like QNX 4, Unix, and DOS, the QNX OS is based on a command-line interface that you might want or need to use instead of the GUI.
      - Processing a command
        When you type a command, several different processes interpret it in turn.
      - Character-device drivers
        When you type a command, the first process that interprets it is the character-device driver.
      - Shell
        After the character-device driver processes what you type, the command line is passed to a command interpreter or shell.
        Editing the command line
        The Korn shell supports emacs-style commands that let you edit the command line.
        Command and filename completion
        You can reduce the amount of typing you have to do by using command completion and filename completion.
        Reserved words
        Entering multiple commands
        You can enter more than one command at a time by separating your commands with a semicolon (;).
        Aliases
        You can define an alias in the shell to create new commands or to specify your favorite options.
        Substitutions
        The shell lets you use a shorthand notation to include the values of certain things in the command line.
        Redirecting input and output
        You can override the behavior of commands that read from, or write to, stdin, stdout, and stderr.
        Pipes
        You can use a pipe (|) to build complex commands from smaller ones.
        Quoting special characters
        Certain characters may have special meaning to the shell, depending on their context. If you want a command line to include any of the special characters that the shell processes, then you may have to quote these characters to force the shell to treat them as simple characters.
        History: recalling commands
        The shell lets you recall commands that you've previously entered; use the up and down arrow keys to move through the history buffer. You can edit the command, if you wish, and then press Enter to reexecute it.
        Shell scripts
        You can enter shell commands into a text file, called a shell script, and then invoke the commands in batch mode by executing (or shelling) the file. For more information, see the Writing Shell Scripts chapter in this guide.
      - Utilities
        Once the shell has processed all of its special characters, what remains typically consists of commands and the arguments to them. Most commands correspond to executable files somewhere on your system, although some—such as cd—are built into the shell.
      - Basic commands
        Here we list some QNX OS commands that you'll frequently use.
      - Troubleshooting
        Here are some common problems you might encounter while working on the command line.
    - Working with Files
      In a QNX OS system, almost everything is a file; devices, data, and even services are all typically represented as files. This lets you work with local and remote resources easily from the command line, or through any program that works with files.
    - Using Editors
      An editor is a utility designed to view and modify files.
    - Configuring Your Environment
      The Building Embedded Systems guide describes what happens when you boot your system, and what you can do to customize it. This chapter describes how you can customize the environment that you get when you log in, and then describes some of the setup you might need to do.
    - Writing Shell Scripts
      Shell scripting, at its most basic, is taking a series of commands you might type at a command line and putting them into a file, so you can reproduce them again at a later date, or run them repeatedly without having to type them over again.
    - Working with Filesystems
      The QNX OS provides a variety of filesystems, so that you can easily access DOS, Linux, as well as native Power-Safe disks.
    - TCP/IP Networking
      The term TCP/IP implies two distinct protocols: TCP and IP. Since these protocols have been used so commonly together, TCP/IP has become a standard terminology in today's Internet. Essentially, TCP/IP refers to network communications where the TCP transport is used to deliver data across IP networks.
    - Backing Up Data
      No matter how reliable your hardware and electrical supply are, or how sure you are that you'll never accidentally erase all your work, it's just common sense to keep backups of your files. Backup strategies differ in ease of use, speed, robustness, and cost.
    - Securing Your System
      Now that more and more computers and other devices are hooked up to insecure networks, security has become a very important issue. The word security can have many meanings, but in a computer context, it generally means preventing unauthorized people from making your computer do things that you don't want it to do.
    - Fine-Tuning Your System
      This chapter describes how you can improve your system's performance.
    - Understanding System Limits
      Resources on a system tend to be finite (alas!), and some are more limited than others. This chapter describes some of the limits on a QNX OS system.
    - Examples
      This appendix includes samples of some of the files described in this guide.
    - Glossary
- 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
- Migrating to QNX OS 8.0
QNX Software in the Cloud
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 OS applications and systems.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation and explains how to obtain technical support.

History: recalling commands

QNX SDP8.0User's GuideUser

The shell lets you recall commands that you've previously entered; use the up and down arrow keys to move through the history buffer. You can edit the command, if you wish, and then press Enter to reexecute it.

The shell also includes a builtin fc command that you can use to display and edit previous commands, as well as an r alias to fc that reexecutes a previous command. For example:

r string

reexecutes the last command that starts with the given string.

Page updated: May 17, 2024