Shell Scripting Tutorial for Beginners 7 - How to append output to the end of text file

Introduction

This tutorial will guide you through the process of appending output to a text file using shell scripting in Linux. By the end of this guide, you'll understand how to effectively add data to files without overwriting existing content, which is a crucial skill for managing and manipulating files in a Linux environment.

Step 1: Open the Terminal

• Launch your terminal application on your Linux system.
• Ensure you have the necessary permissions to create and modify files.

Step 2: Create or Identify the Target File

• You can either create a new file or use an existing one. To create a new file, use the following command:

  touch myfile.txt
  

• If you are using an existing file, make sure you know its path.

Step 3: Append Output to the File

• Use the echo command combined with the append operator >> to add text to the end of your file. The syntax is:

  echo "Your text here" >> myfile.txt
  

  • Replace "Your text here" with the actual text you want to append.

Practical Tip

• If you want to append multiple lines, you can use the following method:

  echo -e "First line\nSecond line" >> myfile.txt
  

  • The -e flag enables interpretation of backslash escapes, allowing you to insert new lines.

Step 4: Verify the Changes

• To check that the text has been successfully appended, use the cat command:

  cat myfile.txt
  

• This will display the contents of the file, confirming that your text has been added.

Step 5: Automate with a Bash Script

• To automate this process, you can create a simple bash script. Here’s how:
  1. Open your text editor and create a new script file:

     nano append_script.sh
     

  2. Add the following code to the script:

     #!/bin/bash
     echo "Your text here" >> myfile.txt
     

  3. Save and exit the editor.
  4. Make the script executable:

     chmod +x append_script.sh
     

  5. Run the script:

     ./append_script.sh
     

Conclusion

In this tutorial, you've learned how to append output to a text file using shell scripting in Linux. You explored basic commands, automated the process with a script, and verified your results. This skill is essential for file manipulation tasks in Linux, and you can expand on this by learning about more advanced scripting techniques. Next, consider exploring how to insert lines at specific positions in a file or how to read from multiple files. Happy scripting!