Understanding Cat Command In Linux, With Examples

Are you trying to learn how to view the contents of a file? The cat command in Linux is capable of doing that and so much more. If you need to read files on the spot, combine multiple, or even find patterns in a text, this is the function you’re looking for.

In this article, we break down why you’d need the cat command and how it works. We’ll provide you with the basic code for your commands and even share a few different ways to apply it. So when you’re ready, let’s explore how to concatenate.

Understanding Cat Command in Linux: An Overview

In Linux, we use the cat command when we want to see the contents of a file or combine multiple files. Cat is short for concatenate, which means to link things together. This function is helpful when you have lots of small files and you want to consolidate them. Here’s how you would write a basic cat command in Linux:

cat [OPTION]... [FILE]...

The main aspect of this code is the FILE, which refers to the files you want to concatenate. If there are any other features you want to address in your code, you’ll put them in the OPTION space.

The cat command has many aspects and features that you can adjust to manipulate your files, making it incredibly useful. Let’s get into the foundational aspects of the function below.

How Does this Function Work?

While you can use the cat command in Linux to complete a variety of tasks, they all work on four main features:

• Standard input/output
• Filesystem
• Command-line interface
• Shell redirection

As with other Linux programs, the cat command receives your text through the standard input (stdin) and writes its response to the standard output (stdout). It uses regular files in Linux’s filesystem for its function while typically staying away from directories, devices, and network sockets.

As a user, you input your cat command in a terminal or shell as a command-line interface (CLI). The function uses redirection to read input from files or write output to files. The shell is how the cat command transfers its information from files to your screen or other files.

What Are the Applications for Cat Command?

A wide range of applications exist for the cat command in Linux. If you’re trying to manipulate the text from one or more regular files, chances are this function has a use. Here are some of the more common functions of the cat command function.

Display the contents of a single file

cat filename.txt

Display the contents of multiple files

cat file1.txt file2.txt file3.txt

Combine the contents of multiple files

cat file1.txt file2.txt file3.txt > combinedfile.txt

Create a new file

cat > newfile.txt
Type your desired content here
Press Ctrl+D

Count the lines in a file

cat file.txt | wc -l

Search for text in a file

cat file.txt | grep 'searchterm'

Create a backup of a file

cat file.txt > file_backup.txt

We hope these applications give you an idea of how to use the cat command. Going forward, you should be able to manipulate this program to suit your needs.