Every Linux System Administrator should have a solid grasp of command-line tools, from the very basics of navigating the file system to the ability to run diagnostic tools to examine potential issues. The command line offers unparalleled power and flexibility along with the ability to chain together commands to form powerful one-line scripts. Although it's quicker to pick up and use the GUI tools as compared to their command line equivalents, few offer the combination of concision and power that a well used combination of command-line tools can bring.
For system administrators who utilize DevOps techniques, the command line offers the first step on the road to automation and offers powerful abilities that can be leveraged with full stack automation. Ansible, Puppet, and Chef are powerful tools, but sometimes it is easier to write a small bash script to undertake a task rather than writing a custom function within a configuration management tool. Despite automation, the command line will be a place where you will spend the majority of your time, and remember that no matter how attractive a point and click tool is, it's highly unlikely that you can automate it.
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Most operating systems have a command line, even if they are traditionally seen as the domain of the GUI. For instance, Windows users have the option of using the excellent PowersShell tool to both administer and control Windows servers.
In this chapter, we are going to cover some useful recipes that can help DevOps engineers in their day-to-day lives. These commands will cover a wide variety of topics, covering elements such as basic networking commands, performance metrics, and perhaps the most important of all, the basics of using the Git Distributed Version Control Software (DVCS). Depending on where you approach the DevOps role from, you may find that some of this chapter touches topics that you have already covered in depth or instance, seasoned Systems Administrators will find the items on the Net tools and system performance are familiar ground; however, these can be valuable introductions for a developer. Likewise, developers will probably find the section on Git to be nothing new, while, many Systems administrators may not be used to version control systems and will benefit hugely from the items in this section.