Book Image

The Software Developer's Guide to Linux

By : David Cohen, Christian Sturm
5 (2)
Book Image

The Software Developer's Guide to Linux

5 (2)
By: David Cohen, Christian Sturm

Overview of this book

Developers are always looking to raise their game to the next level, yet most are completely lost when it comes to the Linux command line. This book is the bridge that will take you to the next level in your software development career. Most of the skills in the book can be immediately put to work to make you a more efficient developer. It’s written specifically for software engineers, not Linux system administrators, so each chapter will equip you with just enough theory to understand what you’re doing before diving into practical commands that you can use in your day-to-day work as a software developer. As you work through the book, you’ll quickly absorb the basics of how Linux works while you get comfortable moving around the command line. Once you’ve got the core skills, you’ll see how to apply them in different contexts that you’ll come across as a software developer: building and working with Docker images, automating boring build tasks with shell scripts, and troubleshooting issues in production environments. By the end of the book, you’ll be able to use Linux and the command line comfortably and apply your newfound skills in your day-to-day work to save time, troubleshoot issues, and be the command-line wizard that your team turns to.
Table of Contents (20 chapters)
18
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19
Index

Shebangs and executable text files, aka scripts

In Unix-like systems, a “script” is just an executable plaintext file. The operating system (often called “the kernel” in Linux) looks at the very first line to determine which interpreter to feed the file’s content into.

That first line is the so-called “shebang” (or hashbang), and it consists of a hash and an exclamation mark (#!) character, followed by the path to the interpreter that is used to execute the file’s code. Here’s an example shebang line:

#!/usr/bin/env bash

When the kernels of Unix-like systems run a file with the executable bit set, they’ll take a look at the first bytes. This might contain a magic number. This number can be part of binary files or some human-readable character, like in the shebang. The kernel uses this information to know whether there is a proper way to execute it. This, for example, prevents situations where the kernel...