Reading Files

Displaying File Contents

cat (short for concatenate) reads one or more files and prints their contents to the screen.

Basic Usage

cat hello.txt

If hello.txt contains Hello, Linux!, the output is:

Hello, Linux!

Reading Multiple Files

cat can read multiple files at once, printing them one after another (hence "concatenate"):

cat hello.txt notes.txt

Absolute Paths

You can always give an absolute path:

cat /etc/hosts

Output:

127.0.0.1 localhost
::1 localhost

The /etc/hosts file maps hostnames to IP addresses. It is one of the most commonly viewed system files.

Other File Viewing Commands

For large files, cat dumps everything at once. Alternatives:

• head file — print just the first 10 lines
• tail file — print just the last 10 lines
• less file — interactive pager (scroll up and down)

Your Task

Read the contents of hello.txt using cat.