diff --git a/Cargo.toml b/Cargo.toml
index 9ffbe91..9178994 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,3 +5,4 @@ edition = "2021"
 
 [dependencies]
 clap = { version = "4.5.0", features = ["derive"] }
+sysinfo = "0.32.0"
diff --git a/src/args.rs b/src/arguments.rs
similarity index 57%
rename from src/args.rs
rename to src/arguments.rs
index 717fd0a..58587fe 100644
--- a/src/args.rs
+++ b/src/arguments.rs
@@ -1,23 +1,21 @@
-use clap:: {Parser, Args, Subcommand};
+use clap::{Parser, Args, Subcommand};
+
 
 /// implements stack for cd wrapper script
-#[derive(Debug, Parser)]
-#[clap(author, version, about)]
-pub struct CommandArgs
-{
-
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about=None)]
+pub struct Arguments {
     /// subcommand
-    #[clap(subcommand)]
-    action: Action,
+    #[command(subcommand)]
+    pub action: Action,
 
     /// process id of parent shell
-    #[arg(long="pid")]
-    pid: u32,
+    #[arg(short, long)]
+    pub pid: u32,
 }
 
 #[derive(Debug, Clone, Subcommand)]
-pub enum Action
-{
+pub enum Action {
     /// navigate to path and add current path to the stack
     push(PushArgs),
 
@@ -27,13 +25,14 @@ pub enum Action
     /// display stack
     stack(StackArgs),
 
-    // bookmark(BookmarkArgs),
+    /// navigate to bookmark and add current path to the stack
+    bookmark(BookmarkArgs),
 }
 
 #[derive(Debug, Clone, Args)]
-pub struct PushArgs
-{
+pub struct PushArgs {
     /// show stack
+    #[arg(short, long)]
     show_stack: Option<bool>,
 
     /// change to <path>
@@ -41,21 +40,26 @@ pub struct PushArgs
 }
 
 #[derive(Debug, Clone, Args)]
-pub struct PopArgs
-{
+pub struct PopArgs {
     /// show stack
     #[arg(short, long)]
     show_stack: Option<bool>,
 }
 
 #[derive(Debug, Clone, Args)]
-pub struct StackArgs
-{
+pub struct StackArgs {
     /// hide entry numbers
-    #[arg(short, long)]
+    #[arg(short='n', long)]
     hide_numbers: Option<bool>,
 
     /// show n entries
     #[arg(short, long="lines")]
     lines: Option<u32>,
+}
+
+#[derive(Debug, Clone, Args)]
+pub struct BookmarkArgs {
+    /// show stack
+    #[arg(short, long)]
+    show_stack: Option<bool>,
 }
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index c9774ec..9505c8e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,11 +1,13 @@
-mod args;
+mod arguments;
+mod stack;
 
-use std::env;
 use clap::Parser;
-use args::CommandArgs;
+use arguments::Arguments;
+use stack::Stack;
 
 
-fn main()
-{
-    let args = CommandArgs::parse();
-}
+fn main() {
+    let args = Arguments::parse();
+
+    let stack = Stack::new(args.pid);
+}
\ No newline at end of file
diff --git a/src/stack.rs b/src/stack.rs
new file mode 100644
index 0000000..13c4f98
--- /dev/null
+++ b/src/stack.rs
@@ -0,0 +1,99 @@
+
+use std::io::{Result};
+use std::fs;
+use std::fs::File;
+use std::path::{PathBuf};
+use std::str::FromStr;
+use sysinfo::{System, Pid};
+
+
+#[derive(Debug, Clone)]
+pub struct Stack
+{
+    pid: u32,
+    stack: Vec<PathBuf>,
+}
+
+impl Stack
+{
+
+    pub fn new(process_id: u32) -> Result<Self> {
+        let mut stack: Stack = Stack{
+            pid : process_id,
+            stack : Vec::<PathBuf>::new(),
+        };
+
+        stack.stack = stack.build_stack()?;
+
+        return Ok(stack);
+    }
+
+    /**
+     * push entry to stack
+     * returns updated stack
+     */
+    pub fn push_entry(&mut self, path: PathBuf) -> Vec<PathBuf> {
+        self.stack.push(path);
+        return self.stack.clone();
+    }
+
+    /**
+     * pop entry from stack
+     * return poppe entry
+     */
+    pub fn pop_entry(&mut self) -> PathBuf {
+        return self.stack.pop().unwrap();
+    }
+
+    /**
+     * clean up dead stack files, parse and build stack
+     */
+    fn build_stack(&mut self) -> Result< Vec<PathBuf> > {
+        let stack_dir: PathBuf = PathBuf::from_str("/tmp/navigation/").expect("failed to create path object of '/tmp/navigation'");
+        let mut sys = System::new_all();
+        sys.refresh_all();
+        let procs = sys.processes();
+    
+        if stack_dir.is_dir() {
+            // clean up stack files of expired processes
+            let members = fs::read_dir(stack_dir.clone())?;
+            for entry in members {
+                let entry = entry?;
+                let process_id = Pid::from_str(entry.file_name().to_str().expect("failed to convert file name to str"));
+                if !procs.contains_key(&process_id.expect("failed to convert filename to pid")) {
+                    fs::remove_file(entry.path()).expect("failed to remove orphaned file");
+                }
+            }
+        } else {
+            // create temporary directory to store the stack
+            let _ = fs::create_dir(stack_dir.clone())?;
+        }
+    
+        let mut stack_file_path = stack_dir.clone();
+        stack_file_path.push(PathBuf::from(&self.pid.to_string()));
+        if stack_file_path.is_file() {
+            // read and parse stack file
+            let _ = self.parse_stack_file(stack_file_path);
+        } else {
+            // create stack file and store current path
+            let _ = File::create(stack_file_path.clone())?;
+        }
+    
+        return Ok(vec![stack_dir]);
+    }
+
+    /**
+     * parse stack file
+     */
+    fn parse_stack_file(&mut self, stack_file_path: PathBuf) -> Result<()> {
+        let stack = fs::read_to_string(stack_file_path)?;
+        let stack = stack.split("\n");
+        for entry in stack {
+            self.stack.push(PathBuf::from(entry));
+        }
+
+        return Ok(());
+    }
+
+} // end `impl database`
+