Book Image

Embedded Linux Development Using Yocto Project Cookbook - Second Edition

By : Alex Gonzalez
Book Image

Embedded Linux Development Using Yocto Project Cookbook - Second Edition

By: Alex Gonzalez

Overview of this book

The Yocto Project has become the de facto distribution build framework for reliable and robust embedded systems with a reduced time to market.You'll get started by working on a build system where you set up Yocto, create a build directory, and learn how to debug it. Then, you'll explore everything about the BSP layer, from creating a custom layer to debugging device tree issues. In addition to this, you’ll learn how to add a new software layer, packages, data, scripts, and configuration files to your system. You will then cover topics based on application development, such as using the Software Development Kit and how to use the Yocto project in various development environments. Toward the end, you will learn how to debug, trace, and profile a running system. This second edition has been updated to include new content based on the latest Yocto release.
Table of Contents (7 chapters)

Managing users and groups


It is also common to need to add or modify users and groups to our filesystem. This recipe explains how it is done.

Getting ready

User information is stored in the /etc/passwd file, a text file that is used as a database for the system user's information. The passwd file is human-readable.

Each line in it corresponds to one user in the system, and it has the following format:

<username>:<password>:<uid>:<gid>:<comment>:<home directory>:<login shell> 

Let's see each of the parameters of this format:

  • username: A unique string that identifies the user at login
  • uid: User ID, a number that Linux uses to identify the user
  • gid: Group ID, a number that Linux uses to identify the user's primary group
  • comment: Comma-separated values that describe the account, typically the user's contact details
  • home directory: Path to the user's home directory
  • login shell: Shell that is started for interactive logins

The default passwd file is stored with the...