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Lab 3.1 - Navigation and Creation in the File System

Objectives​

By the end of this lab, you will be able to:

  • Navigate the Linux file system
  • Create files and directories
  • Understand the FHS (Filesystem Hierarchy Standard) structure
  • Use basic commands (cd, ls, mkdir, touch, etc.)
  • Manipulate files and directories

Prerequisites​

  • Ubuntu 24.04 installed and functional
  • Terminal open
  • Normal user access (no need for root for most exercises)

Exercise 1: Basic Navigation​

Step 1: Important Directories​

# See the current directory
pwd

# Go to the home directory
cd ~
# or
cd $HOME

# View the content
ls

# View with details
ls -l

# View hidden files too
ls -la

Step 2: FHS Structure​

# Go to the root
cd /

# View the structure
ls -la /

# Explore important directories
ls /bin      # Essential binaries
ls /usr/bin  # User binaries
ls /etc      # Configuration files
ls /var      # Variable data
ls /home     # User directories
ls /tmp      # Temporary files

Question: What are the main directories you see?

Step 3: Relative and Absolute Navigation​

# Absolute path (from the root)
cd /home/$USER

# Relative path (from the current directory)
cd Documents  # If Documents exists in the current directory

# Return to the previous directory
cd -

# Go up one level
cd ..

# Go up two levels
cd ../..

Exercise 2: Creating Directories​

Step 1: Create Directories​

# Create a directory
mkdir my-lab

# Create multiple directories
mkdir dir1 dir2 dir3

# Create a tree structure
mkdir -p project/src project/docs project/tests

# Verify
tree project
# If tree is not installed:
# sudo apt install tree

Step 2: Organized Structure​

# Create a structure for a project
mkdir -p ~/projects/linux-lab/{docs,scripts,data,backup}

# View the structure
tree ~/projects/linux-lab

# Or with ls
ls -R ~/projects/linux-lab

Exercise 3: Creating Files​

Step 1: Creation Methods​

# Method 1: touch (empty file)
touch file1.txt

# Method 2: echo
echo "File content" > file2.txt

# Method 3: cat with heredoc
cat > file3.txt << EOF
Line 1
Line 2
Line 3
EOF

# Method 4: Editor
nano file4.txt
# Write text, Ctrl+O to save, Ctrl+X to exit

Step 2: Verify Files​

# View created files
ls -lh

# View content
cat file2.txt

# Count lines
wc -l file3.txt

# View the first lines
head -2 file3.txt

# View the last lines
tail -2 file3.txt

Exercise 4: File Manipulation​

Step 1: Copy and Move​

# Create a test directory
mkdir test-files
cd test-files

# Create a file
echo "Test" > original.txt

# Copy
cp original.txt copy.txt

# Copy to another directory
cp original.txt ~/Documents/

# Copy a directory
cp -r ~/my-lab ~/my-lab-backup

# Move (rename)
mv original.txt renamed.txt

# Move to another directory
mv renamed.txt ~/Documents/

Step 2: Delete​

# Delete a file
rm file1.txt

# Delete multiple files
rm file2.txt file3.txt

# Delete an empty directory
rmdir empty-dir

# Delete a directory with content
rm -r my-lab

# Delete with confirmation
rm -ri project/

Warning: rm -r deletes permanently! No trash bin.

Step 1: find​

# Find all .txt files in the current directory
find . -name "*.txt"

# Find throughout the system (can be long)
find / -name "file.txt" 2>/dev/null

# Find recently modified files
find ~ -mtime -1  # Last 24h

# Find files larger than 1MB
find ~ -size +1M

Step 2: locate (if installed)​

# Install locate
sudo apt update
sudo apt install mlocate

# Update the database
sudo updatedb

# Search
locate file.txt

Exercise 6: Complete Practice​

Step 1: Create a Project Structure​

# Create the structure
mkdir -p ~/linux-project/{src/{scripts,config},docs,logs,backup}

# Create files
touch ~/linux-project/src/scripts/script1.sh
touch ~/linux-project/src/config/config.conf
echo "Initial log" > ~/linux-project/logs/app.log

# View the structure
tree ~/linux-project

Step 2: Organize Files​

cd ~/linux-project

# Create test files
touch test1.txt test2.txt test3.txt

# Create a directory for tests
mkdir tests

# Move test files
mv test*.txt tests/

# Verify
ls -R

Exercise 7: Useful Commands​

Step 1: File Information​

# File type
file file.txt
file /bin/ls

# File size
du -h file.txt

# Directory size
du -sh ~/linux-project

# Disk space
df -h
# Create a symbolic link
ln -s ~/linux-project/src/scripts/script1.sh ~/script1-link

# View the link
ls -l ~/script1-link

# Follow the link
readlink -f ~/script1-link

Verification​

Checklist​

Verify that you can:

  • Navigate the file system (cd, pwd)
  • View directory contents (ls with options)
  • Create directories (mkdir, mkdir -p)
  • Create files (touch, echo, cat, nano)
  • Copy and move files (cp, mv)
  • Delete files and directories (rm, rmdir)
  • Search for files (find, locate)
  • Understand the FHS structure

Reflection Questions​

  1. What is the difference between absolute and relative paths?

    • Absolute: starts with / (from the root)
    • Relative: from the current directory

  2. Why use mkdir -p?

    • Creates parent directories if necessary
    • Avoids errors if the directory already exists

  3. What is the difference between rm and rmdir?

    • rm: deletes files and directories (with -r)
    • rmdir: deletes only empty directories

Next Steps​

  • Lab 3.2: Permissions Management
  • Lab 3.3: Search and Links
  • Chapter 3.2: Directory Structure

Ubuntu 24.04 Resources​

Lab created on: December 2024 - Tested on Ubuntu 24.04