Basic Shell Commands for Automation

Tutorial 1 of 5

1. Introduction

In this tutorial, you will learn how to use basic shell commands for automation. Shell commands provide a powerful and flexible way to interact with the computer, and understanding them is key for tasks such as batch file processing, system administration, and automation.

You will learn how to:

  • Use shell commands for file and directory management
  • Manipulate text and data using shell commands
  • Write simple scripts to automate tasks

Prerequisites: Basic knowledge of computer systems. No prior experience with shell scripting is required.

2. Step-by-Step Guide

2.1 File and Directory Management

  • ls: Lists all files and directories in the current directory.
  • cd: Changes the working directory.
  • mkdir: Creates a new directory.
  • rm: Removes files or directories.
  • cp: Copies files or directories.
  • mv: Moves or renames files or directories.

2.2 Text Processing

  • cat: Concatenates and displays file content.
  • echo: Outputs the strings it is being passed as arguments.
  • grep: Searches for a pattern in files.
  • sed: Stream editor for filtering and transforming text.

2.3 Automation

  • for: Executes commands for each item in a list.
  • while: Executes commands as long as a condition is true.
  • crontab: Schedules tasks to run at fixed times.

3. Code Examples

3.1 File and Directory Management

# List all files and directories
ls

# Change directory to Documents
cd Documents

# Make a directory called new_directory
mkdir new_directory

# Remove a file called unwanted_file.txt
rm unwanted_file.txt

# Copy file.txt to the new_directory
cp file.txt new_directory/

# Move file.txt to the new_directory
mv file.txt new_directory/

3.2 Text Processing

# Display the content of file.txt
cat file.txt

# Print 'Hello, World!' to the console
echo 'Hello, World!'

# Search for 'pattern' in file.txt
grep 'pattern' file.txt

# Replace all occurrences of 'old' with 'new' in file.txt
sed 's/old/new/g' file.txt

3.3 Automation

# Print numbers 1 to 5
for i in {1..5}; do echo $i; done

# Keep printing 'Hello, World!' until stopped
while true; do echo 'Hello, World!'; sleep 1; done

# Schedule a task to run at 12:00 every day
echo "0 12 * * * /path/to/command" | crontab -

4. Summary

In this tutorial, you have learned how to use basic shell commands for file and directory management, text processing, and automation. With these skills, you are ready to start automating tasks on your computer.

Next steps:

  • Learn more advanced shell scripting techniques
  • Learn about other command line tools like awk, find, sort, and more
  • Start automating your everyday tasks

Additional resources:

5. Practice Exercises

  1. Write a script that prints the numbers from 1 to 10.
  2. Write a script that creates a new directory, creates a file with some content in it, then deletes the directory and all its contents.
  3. Write a script that replaces all occurrences of the word 'apple' with 'orange' in a given text file.

Solutions:

  1. for i in {1..10}; do echo $i; done
  2. mkdir temp_directory; echo 'Hello, World!' > temp_directory/temp_file.txt; rm -r temp_directory
  3. sed 's/apple/orange/g' input_file.txt > output_file.txt

Keep practicing to become more proficient. Happy scripting!