diff --git a/Cargo.lock b/Cargo.lock
index 960cb9c..b4028ac 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -140,6 +140,7 @@ dependencies = [
  "memmap2",
  "regex",
  "serde",
+ "serde_json",
  "walkdir",
 ]
 
@@ -168,6 +169,7 @@ dependencies = [
  "iana-time-zone",
  "js-sys",
  "num-traits",
+ "serde",
  "wasm-bindgen",
  "windows-link",
 ]
@@ -305,6 +307,12 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "itoa"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a5f13b858c8d314ee3e8f639011f7ccefe71f97f96e50151fb991f267928e2c"
+
 [[package]]
 name = "js-sys"
 version = "0.3.77"
@@ -457,6 +465,12 @@ version = "1.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8a0d197bd2c9dc6e53b84da9556a69ba4cdfab8619eb41a8bd1cc2027a0f6b1d"
 
+[[package]]
+name = "ryu"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -486,6 +500,18 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_json"
+version = "1.0.141"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "30b9eff21ebe718216c6ec64e1d9ac57087aad11efc64e32002bce4a0d4c03d3"
+dependencies = [
+ "itoa",
+ "memchr",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
diff --git a/Cargo.toml b/Cargo.toml
index cdbf4e3..b9d1ad3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,6 +8,7 @@ clap = { version = "4.0", features = ["derive"] }
 memmap2 = "0.9"
 inotify = "0.10"
 serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
 walkdir = "2.0"
 regex = "1.0"
-chrono = "0.4"
\ No newline at end of file
+chrono = { version = "0.4", features = ["serde"] }
\ No newline at end of file
diff --git a/src/cli/mod.rs b/src/cli/mod.rs
index 2dbfde0..f9a9b1f 100644
--- a/src/cli/mod.rs
+++ b/src/cli/mod.rs
@@ -1,4 +1,5 @@
 pub mod tree;
+pub mod scan;
 
 use clap::{Parser, Subcommand};
 
diff --git a/src/cli/scan.rs b/src/cli/scan.rs
new file mode 100644
index 0000000..78cd12b
--- /dev/null
+++ b/src/cli/scan.rs
@@ -0,0 +1,408 @@
+use crate::{CartoError, PackageManager};
+use crate::database::format::{OrphanCategory, ScanSummary};
+use crate::cli::OutputFormat;
+use crate::package_managers::find_file_owner;
+use std::path::{Path, PathBuf};
+use std::collections::HashMap;
+use walkdir::WalkDir;
+use serde::{Serialize, Deserialize};
+use chrono::{DateTime, Utc};
+
+#[derive(Debug, Clone, Serialize)]
+pub struct OrphanFile {
+    pub path: PathBuf,
+    pub category: OrphanCategory,
+    pub size: u64,
+    pub modified: u64,
+    pub created: u64,
+}
+
+#[derive(Debug, Serialize)]
+pub struct ScanResults {
+    pub scan_time: DateTime<Utc>,
+    pub scanned_paths: Vec<String>,
+    pub total_files_scanned: u64,
+    pub total_orphans: usize,
+    pub orphans_by_category: HashMap<String, Vec<OrphanFile>>,
+    pub total_orphan_size: u64,
+    pub scan_duration_seconds: f64,
+}
+
+impl ScanResults {
+    pub fn new(scanned_paths: Vec<String>) -> Self {
+        Self {
+            scan_time: Utc::now(),
+            scanned_paths,
+            total_files_scanned: 0,
+            total_orphans: 0,
+            orphans_by_category: HashMap::new(),
+            total_orphan_size: 0,
+            scan_duration_seconds: 0.0,
+        }
+    }
+}
+
+pub struct Scanner<'a> {
+    managers: &'a [Box<dyn PackageManager>],
+    exclude_paths: Vec<PathBuf>,
+}
+impl<'a> Scanner<'a> {
+    pub fn new(managers: &'a [Box<dyn PackageManager>]) -> Self {
+        let exclude_paths = vec![
+            PathBuf::from("/proc"),
+            PathBuf::from("/sys"),
+            PathBuf::from("/dev"),
+            PathBuf::from("/run"),
+            PathBuf::from("/var/run"),
+            PathBuf::from("/tmp/.X11-unix"),
+            PathBuf::from("/tmp/.ICE-unix"),
+        ];
+
+        Self {
+            managers,
+            exclude_paths,
+        }
+    }
+
+    pub fn scan_paths(
+        &self,
+        paths: &[String],
+        include_expected: bool,
+    ) -> Result<ScanResults, CartoError> {
+        let start_time = std::time::Instant::now();
+        let scan_paths = if paths.is_empty() {
+            vec!["/".to_string()]
+        } else {
+            paths.to_vec()
+        };
+
+        let mut results = ScanResults::new(scan_paths.clone());
+        let mut orphans: Vec<OrphanFile> = Vec::new();
+
+        for path_str in &scan_paths {
+            let path = Path::new(path_str);
+            if !path.exists() {
+                eprintln!("Warning: Path {} does not exist, skipping", path_str);
+                continue;
+            }
+
+            println!("Scanning: {}", path_str);
+            self.scan_directory(path, &mut orphans, &mut results)?;
+        }
+
+        // Categorize orphans
+        self.categorize_orphans(&mut orphans, include_expected, &mut results);
+
+        results.total_orphans = orphans.len();
+        results.total_orphan_size = orphans.iter().map(|o| o.size).sum();
+        results.scan_duration_seconds = start_time.elapsed().as_secs_f64();
+
+        Ok(results)
+    }
+
+    fn scan_directory(
+        &self,
+        root: &Path,
+        orphans: &mut Vec<OrphanFile>,
+        results: &mut ScanResults,
+    ) -> Result<(), CartoError> {
+        let walker = WalkDir::new(root)
+            .follow_links(false)
+            .into_iter()
+            .filter_entry(|e| !self.should_exclude_path(e.path()));
+
+        for entry in walker {
+            let entry = match entry {
+                Ok(entry) => entry,
+                Err(e) => {
+                    eprintln!("Warning: Error accessing {}: {}", e.path().unwrap_or(Path::new("unknown")).display(), e);
+                    continue;
+                }
+            };
+
+            if !entry.file_type().is_file() {
+                continue;
+            }
+
+            results.total_files_scanned += 1;
+
+            // Check if file is owned by any package manager
+            let path = entry.path();
+            let is_owned = self.is_file_owned(path)?;
+
+            if !is_owned {
+                if let Ok(metadata) = entry.metadata() {
+                    let orphan = OrphanFile {
+                        path: path.to_path_buf(),
+                        category: OrphanCategory::Unknown, // Will be categorized later
+                        size: metadata.len(),
+                        modified: metadata.modified()
+                            .unwrap_or(std::time::UNIX_EPOCH)
+                            .duration_since(std::time::UNIX_EPOCH)
+                            .unwrap_or_default()
+                            .as_secs(),
+                        created: metadata.created()
+                            .unwrap_or(std::time::UNIX_EPOCH)
+                            .duration_since(std::time::UNIX_EPOCH)
+                            .unwrap_or_default()
+                            .as_secs(),
+                    };
+                    orphans.push(orphan);
+                }
+            }
+
+            // Progress indicator for large scans
+            if results.total_files_scanned % 10000 == 0 {
+                println!("Scanned {} files, found {} orphans", 
+                         results.total_files_scanned, orphans.len());
+            }
+        }
+
+        Ok(())
+    }
+
+    fn should_exclude_path(&self, path: &Path) -> bool {
+        for exclude in &self.exclude_paths {
+            if path.starts_with(exclude) {
+                return true;
+            }
+        }
+
+        // Additional exclusions for common mount points and special directories
+        let path_str = path.to_string_lossy();
+        if path_str.contains("/.git/") ||
+           path_str.contains("/.cache/") ||
+           path_str.contains("/.local/share/Trash/") ||
+           path_str.starts_with("/media/") ||
+           path_str.starts_with("/mnt/") {
+            return true;
+        }
+
+        false
+    }
+
+    fn is_file_owned(&self, path: &Path) -> Result<bool, CartoError> {
+        // Check all package managers to see if any owns this file
+        match find_file_owner(path) {
+            Ok(Some(_)) => Ok(true),
+            Ok(None) => Ok(false),
+            Err(e) => {
+                // Don't fail the entire scan for individual file errors
+                eprintln!("Warning: Error checking ownership of {}: {}", path.display(), e);
+                Ok(false)
+            }
+        }
+    }
+
+    fn categorize_orphans(
+        &self,
+        orphans: &mut [OrphanFile],
+        include_expected: bool,
+        results: &mut ScanResults,
+    ) {
+        for orphan in orphans.iter_mut() {
+            orphan.category = self.categorize_file(&orphan.path);
+        }
+
+        // Group by category
+        for orphan in orphans.iter() {
+            if !include_expected && orphan.category == OrphanCategory::Expected {
+                continue;
+            }
+
+            let category_name = orphan.category.name().to_string();
+            results.orphans_by_category
+                .entry(category_name)
+                .or_insert_with(Vec::new)
+                .push(orphan.clone());
+        }
+    }
+
+    fn categorize_file(&self, path: &Path) -> OrphanCategory {
+        let path_str = path.to_string_lossy();
+
+        // Expected orphans in common temporary/log locations
+        if path_str.starts_with("/tmp/") ||
+           path_str.starts_with("/var/tmp/") ||
+           path_str.starts_with("/var/log/") ||
+           path_str.starts_with("/var/cache/") ||
+           path_str.starts_with("/var/spool/") {
+            return OrphanCategory::Expected;
+        }
+
+        // User data in home directories
+        if path_str.starts_with("/home/") ||
+           path_str.starts_with("/root/") {
+            return OrphanCategory::UserData;
+        }
+
+        // System generated files
+        if path_str.starts_with("/var/lib/") ||
+           path_str.starts_with("/var/run/") ||
+           path_str.contains("/.cache/") ||
+           path_str.contains("/cache/") {
+            return OrphanCategory::SystemGenerated;
+        }
+
+        // Configuration backups
+        if let Some(extension) = path.extension() {
+            let ext = extension.to_string_lossy().to_lowercase();
+            if ext == "bak" || ext == "orig" || ext == "old" || ext == "backup" {
+                return OrphanCategory::ConfigBackup;
+            }
+        }
+
+        // Temporary files in unusual locations
+        if let Some(filename) = path.file_name() {
+            let name = filename.to_string_lossy().to_lowercase();
+            if name.starts_with("tmp") || 
+               name.starts_with(".tmp") ||
+               name.ends_with(".tmp") ||
+               name.ends_with("~") {
+                return OrphanCategory::Temporary;
+            }
+        }
+
+        OrphanCategory::Unknown
+    }
+}
+
+pub fn print_scan_results(
+    results: &ScanResults,
+    format: &OutputFormat,
+    detailed: bool,
+    show_sizes: bool,
+) -> Result<(), CartoError> {
+    match format {
+        OutputFormat::Json => print_json_results(results),
+        OutputFormat::Summary => print_summary_results(results, show_sizes),
+        OutputFormat::Detailed => print_detailed_results(results, show_sizes),
+        OutputFormat::Simple => print_simple_results(results),
+        OutputFormat::Tree => print_tree_results(results, show_sizes),
+    }
+}
+
+fn print_json_results(results: &ScanResults) -> Result<(), CartoError> {
+    match serde_json::to_string_pretty(results) {
+        Ok(json) => {
+            println!("{}", json);
+            Ok(())
+        }
+        Err(e) => Err(CartoError::CommandFailed(format!("JSON serialization failed: {}", e))),
+    }
+}
+
+fn print_summary_results(results: &ScanResults, show_sizes: bool) -> Result<(), CartoError> {
+    println!("Scan Summary");
+    println!("============");
+    println!("Scan completed: {}", results.scan_time.format("%Y-%m-%d %H:%M:%S UTC"));
+    println!("Duration: {:.2} seconds", results.scan_duration_seconds);
+    println!("Scanned paths: {}", results.scanned_paths.join(", "));
+    println!("Total files scanned: {}", results.total_files_scanned);
+    println!("Total orphan files: {}", results.total_orphans);
+    
+    if show_sizes {
+        println!("Total orphan size: {}", format_size(results.total_orphan_size));
+    }
+    
+    println!("\nOrphans by Category:");
+    for (category, orphans) in &results.orphans_by_category {
+        let category_size: u64 = orphans.iter().map(|o| o.size).sum();
+        if show_sizes {
+            println!("  {}: {} files ({})", category, orphans.len(), format_size(category_size));
+        } else {
+            println!("  {}: {} files", category, orphans.len());
+        }
+    }
+
+    Ok(())
+}
+
+fn print_detailed_results(results: &ScanResults, show_sizes: bool) -> Result<(), CartoError> {
+    print_summary_results(results, show_sizes)?;
+    
+    println!("\nDetailed File Listings:");
+    for (category, orphans) in &results.orphans_by_category {
+        println!("\n{} ({} files):", category.to_uppercase(), orphans.len());
+        println!("{}", "=".repeat(50));
+        
+        for orphan in orphans.iter().take(20) { // Limit to first 20 per category
+            if show_sizes {
+                println!("  {} ({})", orphan.path.display(), format_size(orphan.size));
+            } else {
+                println!("  {}", orphan.path.display());
+            }
+        }
+        
+        if orphans.len() > 20 {
+            println!("  ... and {} more files", orphans.len() - 20);
+        }
+    }
+
+    Ok(())
+}
+
+fn print_simple_results(results: &ScanResults) -> Result<(), CartoError> {
+    println!("Found {} orphan files in {:.1}s", results.total_orphans, results.scan_duration_seconds);
+    for (category, orphans) in &results.orphans_by_category {
+        println!("{}: {}", category, orphans.len());
+    }
+    Ok(())
+}
+
+fn print_tree_results(results: &ScanResults, show_sizes: bool) -> Result<(), CartoError> {
+    use std::collections::BTreeMap;
+    
+    println!("Orphan Files by Directory Tree");
+    println!("==============================");
+    
+    for (category, orphans) in &results.orphans_by_category {
+        println!("\n{} ({} files):", category.to_uppercase(), orphans.len());
+        
+        // Group files by their parent directory
+        let mut dir_map: BTreeMap<PathBuf, Vec<&OrphanFile>> = BTreeMap::new();
+        for orphan in orphans {
+            if let Some(parent) = orphan.path.parent() {
+                dir_map.entry(parent.to_path_buf()).or_insert_with(Vec::new).push(orphan);
+            }
+        }
+        
+        for (dir, files) in dir_map.iter().take(10) { // Limit directories shown
+            println!("  {}/", dir.display());
+            for file in files.iter().take(5) { // Limit files per directory
+                let filename = file.path.file_name().unwrap_or_default().to_string_lossy();
+                if show_sizes {
+                    println!("    ├── {} ({})", filename, format_size(file.size));
+                } else {
+                    println!("    ├── {}", filename);
+                }
+            }
+            if files.len() > 5 {
+                println!("    └── ... and {} more files", files.len() - 5);
+            }
+        }
+        
+        if dir_map.len() > 10 {
+            println!("  ... and {} more directories", dir_map.len() - 10);
+        }
+    }
+    
+    Ok(())
+}
+
+fn format_size(bytes: u64) -> String {
+    const UNITS: &[&str] = &["B", "KB", "MB", "GB", "TB"];
+    let mut size = bytes as f64;
+    let mut unit_idx = 0;
+    
+    while size >= 1024.0 && unit_idx < UNITS.len() - 1 {
+        size /= 1024.0;
+        unit_idx += 1;
+    }
+    
+    if unit_idx == 0 {
+        format!("{} {}", bytes, UNITS[unit_idx])
+    } else {
+        format!("{:.1} {}", size, UNITS[unit_idx])
+    }
+}
\ No newline at end of file
diff --git a/src/database/format.rs b/src/database/format.rs
index 1386bf6..e00625b 100644
--- a/src/database/format.rs
+++ b/src/database/format.rs
@@ -2,6 +2,7 @@ use memmap2::Mmap;
 use std::fs::File;
 use std::path::Path;
 use crate::{CartoError, PackageSource};
+use serde::Serialize;
 
 #[repr(C, packed)]
 pub struct DatabaseHeader {
@@ -64,7 +65,7 @@ pub struct ScanRecord {
     scan_duration: u32,    // Duration in seconds
 }
 
-#[derive(Debug, Clone, Copy, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize)] 
 pub enum OrphanCategory {
     Unknown = 0,           // Files with no clear ownership
     Expected = 1,          // Files in /tmp, /var/tmp, /var/log, etc.
diff --git a/src/database/mod.rs b/src/database/mod.rs
new file mode 100644
index 0000000..8da6115
--- /dev/null
+++ b/src/database/mod.rs
@@ -0,0 +1 @@
+pub mod format;
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 5f958d9..c830b21 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@
 
 pub mod package_managers;
 pub mod cli;
+pub mod database;
 
 use std::path::{self, PathBuf};
 use package_managers::{detect_available_managers, PackageManager, PackageSource};
@@ -80,7 +81,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             handle_find_command(&managers, name, package, size)?;
         }
         Commands::Scan { force, paths   , format, detailed, sizes, include_expected } => {
-            handle_scan_command(&managers, force, paths, format, detailed, sizes, include_expected)?;
+            handle_scan_command(&managers, paths, format, force, detailed, sizes, include_expected)?;
         }
     }
     
@@ -221,14 +222,16 @@ fn handle_find_command(
 }
 
 fn handle_scan_command(
-    _managers: &[Box<dyn PackageManager>], 
+    managers: &[Box<dyn PackageManager>],
+    paths: Vec<String>,
+    format: OutputFormat,
     _force: bool,
-    _paths: Vec<String>,
-    _format: OutputFormat,
-    _detailed: bool,
-    _sizes: bool,
-    _include_expected: bool
+    detailed: bool,
+    sizes: bool,
+    include_expected: bool,
 ) -> Result<(), Box<dyn std::error::Error>> {
-    println!("Scan functionality not yet implemented");
+    let scanner = cli::scan::Scanner::new(managers);
+    let results = scanner.scan_paths(&paths, include_expected)?;
+    cli::scan::print_scan_results(&results, &format, detailed, sizes)?;
     Ok(())
 }
\ No newline at end of file