What does the cat command do in Linux?

The cat command displays the contents of files, concatenates multiple files, and can create new files. It's one of the most basic and useful Linux commands.

How do I view a file with cat?

Use 'cat filename' to display the contents of a file. For example: cat /etc/passwd will show the contents of the passwd file.

Can cat display line numbers?

Yes, use 'cat -n filename' to display file contents with line numbers, or 'cat -b filename' to number only non-blank lines.

cat Command

The cat command is one of the most frequently used commands in Linux. It reads files sequentially and displays their content on the terminal.

Syntax

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

Description

The cat command concatenate files and print on the standard output. When no file is specified, or when file is -, it reads from standard input.

Common uses include:

Display file contents
Concatenate multiple files
Create new files
Copy file contents

Common Options

Option	Description
`-n`	Number all output lines
`-b`	Number non-blank output lines
`-s`	Suppress repeated empty output lines
`-T`	Display TAB characters as ^I
`-E`	Display $ at end of each line
`-A`	Equivalent to -vET (show all)

Examples

Display file contents

cat filename.txt

Displays the contents of filename.txt

Display multiple files

cat file1.txt file2.txt

Displays contents of file1.txt followed by file2.txt

Display with line numbers

cat -n filename.txt

Shows file contents with line numbers

Create a new file

                        cat > newfile.txt

                        Type your content here

                        Press Ctrl+D to save

Creates a new file and allows you to enter content

Concatenate files

cat file1.txt file2.txt > combined.txt

Combines file1.txt and file2.txt into combined.txt

Append to a file

                        cat >> existing_file.txt

                        Additional content

                        Press Ctrl+D to save

Appends new content to an existing file