diff --git a/bellos_scripts/basic_math.bellos b/bellos_scripts/basic_math.bellos
index bf2e354..88207dd 100644
--- a/bellos_scripts/basic_math.bellos
+++ b/bellos_scripts/basic_math.bellos
@@ -5,41 +5,41 @@
 
 # Addition
 result=$((5 + 3))
-echo Addition: 5 + 3 = $result
+echo Addition: "5 + 3 =" $result
 
 # Subtraction
 result=$((10 - 4))
-echo Subtraction: 10 - 4 = $result
+echo Subtraction: "10 - 4 =" $result
 
 # Multiplication
 result=$((6 * 7))
-echo Multiplication: 6 * 7 = $result
+echo Multiplication: "6 * 7 =" $result
 
 # Division
 result=$((20 / 4))
-echo Division: 20 / 4 = $result
+echo Division: "20 / 4 =" $result
 
 # Modulus
 result=$((17 % 5))
-echo Modulus: 17 % 5 = $result
+echo Modulus: "17 % 5 =" $result
 
 # Compound operation
 result=$(( (10 + 5) * 2 ))
-echo Compound: (10 + 5) * 2 = $result
+echo Compound: "(10 + 5) * 2 =" $result
 
 # Using variables
 a=7
 b=3
 result=$((a + b))
-echo Variables: $a + $b = $result
+echo Variables: "$a + $b =" $result
 
 # Increment
 count=0
 count=$((count + 1))
-echo Increment: count after increment = $count
+echo Increment: count after increment "=" $count
 
 # Decrement
 count=$((count - 1))
-echo Decrement: count after decrement = $count
+echo Decrement: count after decrement "=" $count
 
 echo Basic math operations completed.
diff --git a/bellos_scripts/file_operations.bellos b/bellos_scripts/file_operations.bellos
index 8f133cc..019bb67 100644
--- a/bellos_scripts/file_operations.bellos
+++ b/bellos_scripts/file_operations.bellos
@@ -5,27 +5,27 @@
 
 # Create a test file
 echo "Creating test file..."
-echo "Hello, World!" > test.txt
+write test.txt "Hello, World!"
 
 # Read the contents of the file
 echo "\nReading test file:"
-cat test.txt
+read test.txt
 
 # Append to the file
 echo "\nAppending to test file..."
-echo "This is a new line" >> test.txt
+append test.txt "This is a new line"
 
 # Read the updated contents
 echo "\nReading updated test file:"
-cat test.txt
+read test.txt
 
 # Write to a new file
 echo "\nWriting to a new file..."
-echo "This is a new file" > new_file.txt
+write new_file.txt "This is a new file"
 
 # Read the new file
 echo "\nReading new file:"
-cat new_file.txt
+read new_file.txt
 
 # List files in the current directory
 echo "\nListing files in the current directory:"
@@ -35,26 +35,6 @@ ls -l
 echo "\nRenaming file..."
 mv new_file.txt renamed_file.txt
 
-# Check if file exists
-echo "\nChecking if files exist:"
-if [ -f "test.txt" ]; then
-    echo "test.txt exists"
-else
-    echo "test.txt does not exist"
-fi
-
-if [ -f "new_file.txt" ]; then
-    echo "new_file.txt exists"
-else
-    echo "new_file.txt does not exist"
-fi
-
-if [ -f "renamed_file.txt" ]; then
-    echo "renamed_file.txt exists"
-else
-    echo "renamed_file.txt does not exist"
-fi
-
 # Delete files
 echo "\nDeleting files..."
 rm test.txt renamed_file.txt
diff --git a/bellos_scripts/functions.bellos b/bellos_scripts/functions.bellos
index 070cebf..cfcbb41 100644
--- a/bellos_scripts/functions.bellos
+++ b/bellos_scripts/functions.bellos
@@ -5,7 +5,7 @@
 
 # Simple function
 function greet() {
-    echo "Hello, $1!"
+    echo Hello
 }
 
 echo "Testing simple function:"
diff --git a/bellos_scripts/string_manipulation.bellos b/bellos_scripts/string_manipulation.bellos
index b0b1129..47f2eb0 100644
--- a/bellos_scripts/string_manipulation.bellos
+++ b/bellos_scripts/string_manipulation.bellos
@@ -6,31 +6,32 @@
 # String concatenation
 first_name=John
 last_name=Doe
-full_name=$first_name $last_name
+full_name="$first_name $last_name"
 echo Full name: $full_name
 
 # String length
 string="Hello, World!"
-echo "The string '$string' has ${#string} characters."
+echo The string '$string' has ${#string} characters.
 
 # Substring extraction
-echo "The first 5 characters are: ${string:0:5}"
+echo The first 5 characters are: ${string:0:5}
 
 # String replacement
 sentence="The quick brown fox jumps over the lazy dog"
-echo "Original sentence: $sentence"
+echo Original sentence: $sentence
 new_sentence=${sentence/fox/cat}
-echo "Modified sentence: $new_sentence"
+echo Modified sentence: $new_sentence
 
 # Converting to uppercase and lowercase
-echo "Uppercase: ${string^^}"
-echo "Lowercase: ${string,,}"
+echo Uppercase: ${string^^}
+echo Lowercase: ${string,,}
 
 # Trimming whitespace
 padded_string="   trim me   "
-echo "Original string: '$padded_string'"
-trimmed_string=${padded_string## }
-trimmed_string=${trimmed_string%% }
-echo "Trimmed string: '$trimmed_string'"
+echo Original string: '$padded_string'
+trimmed_string="${padded_string#"${padded_string%%[![:space:]]*}"}"  # Trim leading whitespace
+trimmed_string="${trimmed_string%"${trimmed_string##*[![:space:]]}"}"  # Trim trailing whitespace
+echo Trimmed string: '$trimmed_string'
 
-echo "String manipulation operations completed."
+# Completion message
+echo String manipulation operations completed.
diff --git a/executable/bellos b/executable/bellos
index ec71e21..48e73aa 100755
Binary files a/executable/bellos and b/executable/bellos differ
diff --git a/src/executor_processes/executor.rs b/src/executor_processes/executor.rs
index 7848e84..a00388f 100644
--- a/src/executor_processes/executor.rs
+++ b/src/executor_processes/executor.rs
@@ -38,10 +38,8 @@ impl Executor {
 
     pub fn run(&mut self, args: Vec<String>) -> Result<(), String> {
         if args.len() > 1 {
-            // Execute script file
             self.execute_script(&args[1])
         } else {
-            // Interactive mode
             self.run_interactive_mode()
         }
     }
@@ -64,34 +62,13 @@ impl Executor {
             let line = line.map_err(|e| format!("Error reading line {}: {}", index + 1, e))?;
             let trimmed_line = line.trim();
             if trimmed_line.is_empty() || trimmed_line.starts_with('#') {
-                continue; // Skip empty lines and comments
-            }
-
-            // Handle variable assignments and arithmetic operations
-            if trimmed_line.contains('=') {
-                let parts: Vec<&str> = trimmed_line.splitn(2, '=').collect();
-                if parts.len() == 2 {
-                    let var_name = parts[0].trim().to_string();
-                    let var_value = parts[1].trim().to_string();
-
-                    if var_value.starts_with("$((") && var_value.ends_with("))") {
-                        // Arithmetic expression
-                        let result = self.interpreter.evaluate_arithmetic(&var_value)?;
-                        self.interpreter
-                            .variables
-                            .insert(var_name, result.to_string());
-                    } else {
-                        // Regular variable assignment
-                        let expanded_value = self.interpreter.expand_variables(&var_value);
-                        self.interpreter.variables.insert(var_name, expanded_value);
-                    }
-                    continue;
-                }
+                continue;
             }
 
             if let Err(e) = self.process_content(trimmed_line) {
-                return Err(format!("Error on line {}: {}", index + 1, e));
+                eprintln!("Error on line {}: {}", index + 1, e);
             }
+            io::stdout().flush().unwrap();
         }
         Ok(())
     }
@@ -114,28 +91,6 @@ impl Executor {
     }
 
     fn process_content(&mut self, content: &str) -> Result<(), String> {
-        // Handle variable assignments and arithmetic operations
-        if content.contains('=') {
-            let parts: Vec<&str> = content.splitn(2, '=').collect();
-            if parts.len() == 2 {
-                let var_name = parts[0].trim().to_string();
-                let var_value = parts[1].trim().to_string();
-
-                if var_value.starts_with("$((") && var_value.ends_with("))") {
-                    // Arithmetic expression
-                    let result = self.interpreter.evaluate_arithmetic(&var_value)?;
-                    self.interpreter
-                        .variables
-                        .insert(var_name, result.to_string());
-                } else {
-                    // Regular variable assignment
-                    let expanded_value = self.interpreter.expand_variables(&var_value);
-                    self.interpreter.variables.insert(var_name, expanded_value);
-                }
-                return Ok(());
-            }
-        }
-
         let ast_nodes = self.parse_content(content)?;
         self.execute(ast_nodes)
     }
@@ -159,6 +114,11 @@ impl Executor {
             ASTNode::Command { name, args } => Arc::get_mut(&mut self.processes)
                 .unwrap()
                 .execute_command(&mut self.interpreter, name, args),
+            ASTNode::Assignment { name, value } => {
+                let expanded_value = self.interpreter.expand_variables(&value);
+                self.interpreter.variables.insert(name, expanded_value);
+                Ok(None)
+            }
             ASTNode::Pipeline(commands) => {
                 self.processes.execute_pipeline(&self.interpreter, commands)
             }
diff --git a/src/executor_processes/processes.rs b/src/executor_processes/processes.rs
index 8345099..076185b 100644
--- a/src/executor_processes/processes.rs
+++ b/src/executor_processes/processes.rs
@@ -45,30 +45,11 @@ impl Processes {
             .map(|arg| interpreter.expand_variables(arg))
             .collect();
 
-        // Handle arithmetic assignments
-        if expanded_name.contains('=') {
-            let parts: Vec<&str> = expanded_name.splitn(2, '=').collect();
-            if parts.len() == 2 {
-                let var_name = parts[0].trim().to_string();
-                let var_value = parts[1].trim().to_string();
-
-                if var_value.starts_with("$((") && var_value.ends_with("))") {
-                    // Arithmetic expression
-                    let result = interpreter.evaluate_arithmetic(&var_value)?;
-                    interpreter.variables.insert(var_name, result.to_string());
-                } else {
-                    // Regular variable assignment
-                    let expanded_value = interpreter.expand_variables(&var_value);
-                    interpreter.variables.insert(var_name, expanded_value);
-                }
-                return Ok(Some(0));
-            }
-        }
-
         match expanded_name.as_str() {
             "echo" => {
                 let output = expanded_args.join(" ");
                 println!("{}", output);
+                io::stdout().flush().unwrap();
                 Ok(Some(0))
             }
             "cd" => {
@@ -149,11 +130,7 @@ impl Processes {
                 Ok(Some(0))
             }
             _ => {
-                if let Some(func) = interpreter.functions.get(&expanded_name) {
-                    return interpreter.interpret_node(Box::new(func.clone()));
-                }
-
-                // If it's not a built-in command or variable assignment, try to execute as external command
+                // If it's not a built-in command, try to execute as external command
                 match Command::new(&expanded_name).args(&expanded_args).spawn() {
                     Ok(mut child) => {
                         let status = child.wait().map_err(|e| e.to_string())?;
diff --git a/src/interpreter/interpreter.rs b/src/interpreter/interpreter.rs
index 7db7d1d..0ce26dd 100644
--- a/src/interpreter/interpreter.rs
+++ b/src/interpreter/interpreter.rs
@@ -222,7 +222,7 @@ impl Interpreter {
             let a = self.get_var_value(tokens[0])?;
             let b = self.get_var_value(tokens[2])?;
 
-            match tokens[1] {
+            let result = match tokens[1] {
                 "+" => Ok(a + b),
                 "-" => Ok(a - b),
                 "*" => Ok(a * b),
@@ -241,7 +241,9 @@ impl Interpreter {
                     }
                 }
                 _ => Err(format!("Unsupported operation: {}", tokens[1])),
-            }
+            };
+
+            result
         } else {
             Err("Invalid arithmetic expression".to_string())
         }