[Linux] Bash cat uso: Displaying file contents

Overview

The cat command in Bash is used to concatenate and display the contents of files. It is a simple yet powerful tool that allows users to read file contents directly in the terminal or combine multiple files into one.

Usage

The basic syntax of the cat command is as follows:

cat [options] [arguments]

Common Options

• -n: Number all output lines.
• -b: Number non-empty output lines.
• -E: Display a dollar sign ($) at the end of each line.
• -s: Suppress repeated empty output lines.
• -A: Show all characters, including non-printing characters.

Common Examples

1. Display a single file:

   cat filename.txt
   

2. Display multiple files:

   cat file1.txt file2.txt
   

3. Create a new file by concatenating existing files:

   cat file1.txt file2.txt > newfile.txt
   

4. Append contents of one file to another:

   cat file1.txt >> file2.txt
   

5. Display line numbers:

   cat -n filename.txt
   

6. Suppress repeated empty lines:

   cat -s filename.txt
   

Tips

• Use cat in combination with other commands through piping to process file contents further.
• For large files, consider using less or more instead of cat to avoid overwhelming the terminal.
• Be cautious when using redirection (>) to avoid overwriting existing files unintentionally. Always double-check your command before executing it.