diff --git a/Cargo.lock b/Cargo.lock
index c6ad41f..1c45ac4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -181,6 +181,7 @@ dependencies = [
  "similar",
  "strip-ansi-escapes",
  "tempfile",
+ "term_size",
 ]
 
 [[package]]
@@ -435,6 +436,16 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "term_size"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e4129646ca0ed8f45d09b929036bafad5377103edd06e50bf574b353d2b08d9"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.13"
diff --git a/Cargo.toml b/Cargo.toml
index ad75285..4846896 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -26,6 +26,7 @@ serde = { version = "1.0.210", features = ["derive"] }
 peg = "0.8.4"
 chumsky = "0.9.3"
 similar = "2.6.0"
+term_size = "0.3.2"
 
 [dev-dependencies]
 strip-ansi-escapes = "0.2.0"
diff --git a/src/lib.rs b/src/lib.rs
index 666cee5..c9664a8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -252,6 +252,37 @@ pub fn delete_env_vars(
     Ok(updated_lines)
 }
 
+pub fn format_env_file(content: &str, prune: bool) -> Result<Vec<parser::Line>, std::io::Error> {
+    let lines = parser::parser().parse(content).map_err(|e| {
+        std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            format!("Error parsing .env file: {:?}", e),
+        )
+    })?;
+
+    let mut key_value_lines: Vec<parser::Line> = lines
+        .into_iter()
+        .filter(|line| match line {
+            parser::Line::KeyValue { value, .. } => !value.is_empty(),
+            parser::Line::Comment(_) => !prune,
+        })
+        .collect();
+
+    key_value_lines.sort_by(|a, b| {
+        if let (
+            parser::Line::KeyValue { key: key_a, .. },
+            parser::Line::KeyValue { key: key_b, .. },
+        ) = (a, b)
+        {
+            key_a.cmp(key_b)
+        } else {
+            std::cmp::Ordering::Equal
+        }
+    });
+
+    Ok(key_value_lines)
+}
+
 fn needs_quoting(value: &str) -> bool {
     value.chars().any(|c| {
         c.is_whitespace()
diff --git a/src/main.rs b/src/main.rs
index e47e0e9..4be14ee 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,18 +13,31 @@ use envset::{
 
 fn print_diff(old_content: &str, new_content: &str, use_color: bool) {
     let diff = TextDiff::from_lines(old_content, new_content);
+    let term_width = term_size::dimensions().map(|(w, _)| w).unwrap_or(80);
 
     for change in diff.iter_all_changes() {
         if use_color {
             match change.tag() {
-                ChangeTag::Delete => print!("{}", change.to_string().trim_end().on_bright_red()),
-                ChangeTag::Insert => print!("{}", change.to_string().trim_end().on_bright_green()),
+                ChangeTag::Delete => {
+                    let line = change.to_string();
+                    let padding = " ".repeat(term_width.saturating_sub(line.trim_end().len()));
+                    print!(
+                        "{}",
+                        (line.trim_end().to_string() + &padding).on_bright_red()
+                    );
+                    println!();
+                }
+                ChangeTag::Insert => {
+                    let line = change.to_string();
+                    let padding = " ".repeat(term_width.saturating_sub(line.trim_end().len()));
+                    print!(
+                        "{}",
+                        (line.trim_end().to_string() + &padding).on_bright_green()
+                    );
+                    println!();
+                }
                 ChangeTag::Equal => print!("{}", change),
             }
-            // Print a newline after each colored line
-            if change.tag() != ChangeTag::Equal {
-                println!();
-            }
         } else {
             let sign = match change.tag() {
                 ChangeTag::Delete => "-",
@@ -75,6 +88,12 @@ enum Commands {
         #[arg(required = true)]
         keys: Vec<String>,
     },
+    /// Format the .env file (sort keys and remove empty lines)
+    Fmt {
+        /// Remove whole line comments
+        #[arg(short = 'p', long = "prune")]
+        prune: bool,
+    },
 }
 
 fn main() {
@@ -146,6 +165,34 @@ fn main() {
                 process::exit(1);
             }
         },
+        Some(Commands::Fmt { prune }) => match read_env_file_contents(&cli.file) {
+            Ok(old_content) => match envset::format_env_file(&old_content, *prune) {
+                Ok(formatted_lines) => {
+                    let mut buffer = Vec::new();
+                    if let Err(e) = print_env_file_contents(&formatted_lines, &mut buffer) {
+                        eprintln!("Error writing formatted .env file contents: {}", e);
+                        process::exit(1);
+                    }
+                    let new_content = String::from_utf8_lossy(&buffer);
+
+                    let use_color = atty::is(Stream::Stdout);
+                    print_diff(&old_content, &new_content, use_color);
+
+                    if let Err(e) = std::fs::write(&cli.file, buffer) {
+                        eprintln!("Error writing formatted .env file: {}", e);
+                        process::exit(1);
+                    }
+                }
+                Err(e) => {
+                    eprintln!("Error formatting .env file: {}", e);
+                    process::exit(1);
+                }
+            },
+            Err(e) => {
+                eprintln!("Error reading .env file: {}", e);
+                process::exit(1);
+            }
+        },
         None => {}
     }