📁 Lesson 2.3: Working with Files and Directories

Creating Files

touch — Create an Empty File

The simplest way to create a new, empty file:

# Create a single file
touch notes.txt

# Create multiple files at once
touch file1.txt file2.txt file3.txt

# Verify they exist
ls -l notes.txt file1.txt file2.txt file3.txt

Creating Files with Content

You can create files with content using redirection:

# Create a file with one line of text
echo "Hello, Linux!" > greeting.txt

# View the contents
cat greeting.txt
# Output: Hello, Linux!

# Append more text (>> adds to the end, > overwrites)
echo "This is a second line." >> greeting.txt

cat greeting.txt
# Output:
# Hello, Linux!
# This is a second line.

Creating Directories

mkdir — Make Directory

# Create a single directory
mkdir projects

# Create multiple directories
mkdir photos videos music

# Create nested directories (parent + child in one command)
mkdir -p projects/website/css

# The -p flag creates all necessary parent directories
# Without -p, this would fail if "projects" or "website" didn't exist

# Create a project structure in one shot
mkdir -p myproject/{src,tests,docs,assets/{images,fonts}}

# See what we built
tree myproject

myproject
├── assets
│   ├── fonts
│   └── images
├── docs
├── src
└── tests

6 directories, 0 files

Copying Files and Directories

cp — Copy

# Copy a file
cp notes.txt notes_backup.txt

# Copy a file to another directory
cp notes.txt ~/Documents/

# Copy a file to another directory with a new name
cp notes.txt ~/Documents/my_notes.txt

# Copy multiple files to a directory
cp file1.txt file2.txt file3.txt ~/Documents/

Copying Directories

To copy a directory and everything inside it, you need the -r (recursive) flag:

# Copy an entire directory
cp -r projects projects_backup

# -r means "recursive" — it copies the directory and all its contents
# Without -r, cp refuses to copy directories

# A safe, verbose recursive copy
cp -riv projects projects_backup

Moving and Renaming

mv — Move (and Rename)

In Linux, moving and renaming are the same operation:

# Rename a file (move it to a new name in the same directory)
mv notes.txt my_notes.txt

# Move a file to another directory
mv my_notes.txt ~/Documents/

# Move and rename at the same time
mv my_notes.txt ~/Documents/important_notes.txt

# Move a directory (no -r needed, unlike cp)
mv projects ~/Documents/projects

# Move multiple files to a directory
mv file1.txt file2.txt file3.txt ~/Documents/

Deleting Files and Directories

rm — Remove Files

# Delete a single file
rm notes.txt

# Delete with confirmation prompt
rm -i notes.txt
# Output: rm: remove regular file 'notes.txt'? y

# Delete multiple files
rm file1.txt file2.txt file3.txt

# Delete all .txt files in the current directory
rm *.txt

rm -r — Remove Directories

# Remove a directory and everything inside it
rm -r old_project

# Remove with confirmation for each file
rm -ri old_project

# Force remove (no prompts, even for read-only files)
rm -rf old_project

rmdir — Remove Empty Directories

# Only works if the directory is empty
rmdir empty_folder

# Fails if the directory contains anything
rmdir projects
# Output: rmdir: failed to remove 'projects': Directory not empty

Wildcards

Wildcards (also called globs) let you match multiple files with a pattern:

# List all HTML files
ls *.html

# Copy all images to a backup
cp *.jpg *.png ~/backup/

# Move all files starting with "report"
mv report* ~/Documents/

# Delete all .tmp files
rm *.tmp

# List files with exactly 3-character extensions
ls *.???

Finding Files

When you need to find a file but don't know exactly where it is:

find — Search by Criteria

# Find files by name (starting from current directory)
find . -name "notes.txt"

# Find all .txt files under your home directory
find ~ -name "*.txt"

# Find files by name (case-insensitive)
find ~ -iname "readme*"

# Find only directories with a name
find /etc -type d -name "apt"

# Find only files (not directories)
find ~ -type f -name "*.log"

# Find files larger than 100MB
find / -type f -size +100M 2>/dev/null

# Find files modified in the last 7 days
find ~ -type f -mtime -7

locate — Fast Search by Name

The locate command uses a pre-built database and is much faster than find:

# Install locate
sudo apt install mlocate -y

# Update the database (run this first, and after adding new files)
sudo updatedb

# Search for a file
locate notes.txt

# Case-insensitive search
locate -i readme

which and type — Find Commands

# Where is a command located?
which ls
# Output: /usr/bin/ls

which python3
# Output: /usr/bin/python3

# More detailed info about a command
type ls
# Output: ls is aliased to 'ls --color=auto'

type cd
# Output: cd is a shell builtin

Exercises

my_website/
├── index.html
├── about.html
├── css/
│   └── style.css
├── js/
│   └── app.js
└── images/

mkdir -p my_website/{css,js,images}
touch my_website/index.html
touch my_website/about.html
touch my_website/css/style.css
touch my_website/js/app.js

# Verify
tree my_website

# Create test files
touch report_jan.txt report_feb.txt report_mar.txt
touch photo1.jpg photo2.jpg photo3.png
touch notes.md readme.md

# Now try:
ls *.txt            # All text files
ls report*          # All reports
ls photo?.jpg       # Photos 1-9 (single digit)
ls *.md             # All markdown files

# Move all reports to a folder
mkdir reports
mv report_*.txt reports/

# Verify
ls reports/

# Find all .txt files in your home directory
find ~ -name "*.txt" -type f 2>/dev/null

# Find where the "bash" command lives
which bash

# Find all directories named "Documents" under /home
find /home -type d -name "Documents" 2>/dev/null

# First, see what's there
ls

# Remove files
rm photo*.jpg photo*.png notes.md readme.md info.txt

# Remove directories
rm -r my_website reports archive

# Verify it's clean
ls

Knowledge Check

Quick Reference

Summary

🚀 What's Next?

In Module 3, you'll learn how Linux controls who can access what — users, groups, and the powerful permission system that keeps everything secure.