Linux: Input, Output and Pipeline

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From the course by Google

Operating Systems and You: Becoming a Power User

1716 ratings

Google

Operating Systems and You: Becoming a Power User

1716 ratings

Course 3 of 5 in the Specialization Google IT Support Professional Certificate

In this course, you’ll learn how to use the major operating systems, Windows and Linux, which are a core component of IT. Through a combination of video lectures, demonstrations, and hands-on practice, you’ll learn about the main components of an operating system and how to perform critical tasks like managing software and users, and configuring hardware. By the end of this course you’ll be able to: - navigate the Windows and Linux filesystems using a graphical user interface and command line interpreter. - set up users, groups, and permissions for account access. - install, configure, and remove software on the Windows and Linux operating systems. - configure disk partitions and filesystems. - understand how system processes work and how to manage them. - work with system logs and remote connection tools. - utilize operating system knowledge to troubleshoot common issues in an IT Support Specialist role. Except as otherwise noted, the contents on this site are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

From the lesson

Navigating the System

Welcome to the Operating Systems course of the IT Support Professional Certificate! In the first week of this course, we will cover the basics of Windows and Linux operating systems (OS). We will learn about how directories and files work in Windows and Linux OS. You will also learn practical ways to manipulate files and directories in the Windows graphical user interface (GUI), Windows command line interface (CLI), and Linux shell. By the end of this module, you will interact with files and directories and perform basic text manipulation in Windows and Linux OS.

Windows: Display File Contents3:53

Linux: Display File Contents2:24

Windows: Modifying Text Files2:04

Linux: Modifying Text Files1:53

Windows Powershell3:09

Windows: Searching within Files6:15

Windows: Searching within Directories1:01

Linux: Searching within Files1:02

Windows: Input, Output, and the Pipeline7:02

Linux: Input, Output and Pipeline3:41

Windows and Linux Advanced Navigation1:40

Ben First Tech Job1:13

Meet the Instructors

Google

Similar to Windows, we have three different I/O or input-output streams: standard out,

standard in and standard err.

Remember the standard out example in the last lesson?

Well, the same concept applies in Linux.

We echo the text woof here,

but instead of sending it to our screen by default,

we're going to redirect the output to a file using the standard out redirector operator.

Let's verify and there it is.

This overrides any file named dog.text with the content woof.

If we don't want to overwrite an existing file,

we can use the append operator or greater than greater than.

So, echo woof, dog.text.

We could verify that. There it is.

One redirector operator that we talked about in the Windows lesson,

but didn't show an example of,

was the standard in redirector operator.

The standard in redirector is denoted by a less than sign.

Instead of getting input from the keyboard,

we can get input from files like this.

This command is exactly the same as cat file_input.

The difference here is that we aren't using our keyboard input more,

we're using the file as standard in.

Finally, similar to Windows,

the last redirector operator we'll talk about is standard err.

Standard err displays error messages which you can get by

using the two greater than, redirector operator.

Just like Windows, the two is used to denote standard err.

So, to redirect just the error messages of some output,

you can use something like this,

ls/ dir/ fake_dir 2> error_output.text.

Now, if I view that, new document.

Now, we can see the error message in error output.text.

Remember the dollar sign null variable that we used in Windows to

toss unwanted output into a metaphorical black hole?

We have something like that in Linux too.

There's a special file in Linux called the /dev/null file.

Let's say we want to filter out the error messages in

a file and just want to see standard out messages.

We could do something like this.

Now, our output is filtered from error messages.

Remember how we talked about taking the output of

one command and using it as the input of another command,

with the Windows pipeline?

Well, the same thing exists in Linux.

The pipe command allows us to do this.

Let's say we want to see which sub-directories in

the slash etc directory contain the word Bluetooth.

We can do something like this.

We're using the pipe redirector to take the output

of ls-la/etc and pipe or send it to the grep command.

Now, without even looking through the directory,

we're able to quickly see if the Bluetooth directory is in here. There it is.

You've gotten a glimpse of the power of

redirectors and as you dive deeper into the world of Linux,

you'll be using them at regular basis.

They're super valuable tools to have and now,

they're part of your toolkit.

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