You're reading from Mastering Embedded Linux Programming - Third Edition

Product typeBook

Published inMay 2021

PublisherPackt

ISBN-139781789530384

Edition3rd Edition

Concepts

Embedded Systems

Authors (2):

Frank Vasquez

Chris Simmonds

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The init program

Running a shell, or even a shell script, at boot time is fine for simple cases, but really you need something more flexible. Normally, Unix systems run a program called init that starts up and monitors other programs. Over the years, there have been many init programs, some of which I will describe in Chapter 13, Starting Up – The init Program. For now, I will briefly introduce the init program from BusyBox.

The init program begins by reading the configuration file, /etc/inittab. Here is a simple example that is adequate for our needs:

::sysinit:/etc/init.d/rcS
::askfirst:-/bin/ash

The first line runs a shell script, rcS, when init is started. The second line prints the message Please press Enter to activate this console to the console and starts a shell when you press Enter. The leading - before /bin/ash means that it will become a login shell, which sources /etc/profile and $HOME/.profile before giving the shell prompt. One of the advantages of launching...

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Mastering Embedded Linux Programming - Third Edition

Published in: May 2021Publisher: PacktISBN-13: 9781789530384

Authors (2)

Frank Vasquez

Frank Vasquez is an independent software consultant specializing in consumer electronics. He has over a decade of experience designing and building embedded Linux systems. During that time, he has shipped numerous devices including a rackmount DSP audio server, a diver-held sonar camcorder, and a consumer IoT hotspot. Before his career as an embedded Linux engineer, Frank was a database kernel developer at IBM where he worked on DB2. He lives in Silicon Valley.
Read more about Frank Vasquez

Chris Simmonds

Chris Simmonds is a software consultant and trainer living in southern England. He has almost two decades of experience in designing and building open-source embedded systems. He is the founder and chief consultant at 2net Ltd, which provides professional training and mentoring services in embedded Linux, Linux device drivers, and Android platform development. He has trained engineers at many of the biggest companies in the embedded world, including ARM, Qualcomm, Intel, Ericsson, and General Dynamics. He is a frequent presenter at open source and embedded conferences, including the Embedded Linux Conference and Embedded World.
Read more about Chris Simmonds

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