File System Management

File System Hierarchy Standard (FHS)

Root Directory Structure

/ - Root directory
/home - User home directories
/etc - System configuration files
/var - Variable data files
/usr - User programs and data
/bin - Essential command binaries
/sbin - System binaries
/tmp - Temporary files

Important Directories

/opt - Optional software packages
/proc - Process information
/dev - Device files
/boot - Boot loader files
/lib - System libraries

File Permissions and Ownership

Understanding Permissions

drwxr-xr-x  # Example permission string
# d: directory
# rwx: owner permissions (read, write, execute)
# r-x: group permissions
# r-x: others permissions

Permission Types

Read (r): 4
Write (w): 2
Execute (x): 1

Changing Permissions

chmod 755 file.txt  # Set permissions using octal
chmod u+x script.sh  # Add execute permission for user
chmod g-w file.txt  # Remove write permission for group

File Ownership

chown user:group file.txt  # Change owner and group
chgrp newgroup file.txt    # Change group only

File Manipulation Commands

Basic File Operations

touch file.txt     # Create empty file
cp source dest     # Copy files
mv source dest     # Move/rename files
rm file.txt        # Remove files
mkdir dir          # Create directory
rmdir dir          # Remove empty directory

Advanced File Operations

find . -name "*.txt"   # Find files
grep "pattern" file    # Search in files
tar -czf archive.tar.gz files/  # Create archive
ln -s target link      # Create symbolic link

Hands-on Practice

Exercise 1: File Permissions

Create a new file: touch test.txt
View permissions: ls -l test.txt
Change permissions: chmod 644 test.txt
Change owner: sudo chown root test.txt

Exercise 2: File Operations

Create directory structure:

mkdir -p project/{src,docs,tests}
touch project/src/{main.py,utils.py}

Copy and move files
Create symbolic links

File System Maintenance

Disk Usage

df -h              # Show disk space usage
du -sh directory   # Show directory size
ncdu               # Interactive disk usage analyzer

File System Check

fsck               # Check and repair file system
e2fsck             # Check ext2/3/4 file systems
tune2fs            # Adjust file system parameters

Additional Resources

Next Steps

Practice file permission calculations
Explore advanced file operations
Learn about ACLs (Access Control Lists)
Understand file system attributes