Linux Pipes and Redirection
---
title: "Linux Pipes and Redirection"
category: "linux-tutorials"
description: "Using redirection symbols (>, >>) to control command output and pipes (|) to chain commands together."
---
# Linux Pipes and Redirection
This tutorial explains how to use redirection symbols (`>` and `>>`) to control where the output of Linux commands goes, and how to use pipes (`|`) to connect the output of one command to the input of another.
## Redirecting Input and Output
By default, Linux commands display their results (standard output) to the screen and take input from the keyboard (standard input). Redirection allows you to change these defaults, often sending output to a file instead of the screen.
### Overwriting Output with `>`
A right angle-bracket `>` (called an "into") on the command line indicates that the output of the command should be placed into the file specified after the symbol, instead of being displayed on the screen.
**Syntax:**
```bash
command > filename
Example:
ls > list
This command will execute ls (list directory contents) and place its output into a file named list in the current directory.
Warning: If a file named list already exists, its previous contents will be overwritten without warning.
Appending Output with >>
You can append output to the end of an existing file using a double right angle-bracket >> (called an "onto"). If the file does not exist, it will be created.
Syntax:
command >> filename
Example:
Following the previous example, if the next command entered was:
date >> list
The output of the date command (the current date and time) would be added to the end of the file called list, preserving the original content from the ls command.
Pipes (|)
Pipes allow you to connect multiple commands together. The standard output of the command to the left of the pipe symbol is "piped" into the standard input of the command to the right of the pipe. The symbol for this connection is a vertical bar | called a pipe.
Syntax:
command1 | command2
This takes the output of command1 and uses it as the input for command2.
Example 1: Paging through long output
If a directory contains many files, the output of ls might scroll off the screen too quickly to read. You can pipe the output of ls to the more command, which displays output one screen-full at a time.
ls | more
In this case, ls generates the directory listing, which is then passed as input to more. more displays the first page and waits for user input (space bar for next page, q to quit).
Example 2: Searching within a file
You can use pipes to filter the contents of a file. For instance, use cat to display a file's content and pipe it to grep to search for specific text within that content.
cat filename | grep searchstring
This command displays the content of filename using cat, and then grep filters that output, showing only the lines containing searchstring.
```