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

Logging

Finding Errors in the systemd Journal

We’ll dive deep into the systemd journal in a later chapter, but for now here are a few common invocations.

Search for errors in the entire system log

When you’re trying to get a general idea of what’s wrong on a system, look for errors accross all services:

journalctl -xe

This command will search the system log for error messages, and let you page through them (spacebar, arrow keys, Page Up / Page Down). Like other systemd commands, you can ‘quit’ the output pager with q.

If you want to do the same thing, except:

  • starting at the bottom of the log which contains the most recent entries, and
  • live-updating the log for new entries,

you can use the -f flag to follow the log:

journalctl -xef

Search for errors in specific services or programs (“Units”)

To narrow your search to a specific unit (foobar) that’s misbehaving:

journalctl -xeu foobar

As with other journalctl commands,...