Redirect data streams with pipes

This Way Please

© Lead Image © artqu, 123RF.com

© Lead Image © artqu, 123RF.com

Article from Issue 261/2022
Author(s):

Pipes in the shell offer a surprising amount of versatility, including the ability to transfer data between computers.

Many users are only familiar with pipes as links between multiple flows, but they can do much more than that. Pipes can help you transfer data between computers. In this article, I will show you how to use pipes to redirect data streams in the shell.

Channels

Whenever a process starts under Linux, it is automatically assigned three channels. These channels have system assignments that let you address them, and each has a starting and end point. Channel 0 (STDIN) reads data, channel 1 (STDOUT) outputs data, and channel 2 (STDERR) outputs any error messages. Channel 2 typically points to the same device as channel 1 (Figure 1).

Figure 1: The shell reads input from the keyboard (STDIN, channel 0) and outputs the results on screen (STDOUT, channel 1). Error messages are displayed via STDERR (channel 2).

[...]

Use Express-Checkout link below to read the full article (PDF).

Buy this article as PDF

Download Article PDF now with Express Checkout
Price $2.95
(incl. VAT)

Buy Linux Magazine

SINGLE ISSUES
Print Issues
Digital Issues
SUBSCRIPTIONS
Print Subscriptions
Digital Subscriptions

Related content

  • Mining File Data

    Efficient tools to examine, edit, and transfer file information.

    more »
  • Optimizing Shell Scripts

    Shell scripts are often written for simplicity rather than efficiency. A closer look at the processes can lead to easy optimization.

    more »
  • Parallel Bash

    You don't need a heavy numeric mystery to benefit from the wonders of parallel processing. This article describes some simple techniques for parallelizing everyday bash scripts.

    more »
  • Command Line: Data Flow

    Working in the shell has many benefits. Pipelines, redirectors, and chains of commands give users almost infinite options.

    more »
  • Binary Data in Bash

    Bash is known for admin utilities and text manipulation tools, but the venerable command shell included with most Linux systems also has some powerful commands for manipulating binary data.

    more »
comments powered by Disqus
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters

Support Our Work

Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

Learn More

News

Tag Cloud

Administration Community Desktop Events Hardware Linux Mobile Programming Security Software Ubuntu Web Development Windows free software open source