diff --git a/Makefile b/Makefile
index 0c675c5..0c74154 100644
--- a/Makefile
+++ b/Makefile
@@ -22,6 +22,7 @@ check: format lint check-type
 
 build: check
 	@rm -rf dist/*
+	$(PYTHON) build-deps.py
 	$(PYTHON) -m hatch -v build -t wheel
 
 install: build
diff --git a/build-deps.py b/build-deps.py
new file mode 100644
index 0000000..7aa4cf8
--- /dev/null
+++ b/build-deps.py
@@ -0,0 +1,47 @@
+import argparse
+import os
+import re
+
+DEPS_REGEX = "dependencies = \[[^\]]*\]"
+PYPROJECT_FILENAME = "pyproject.toml"
+
+if __name__ == "__main__":
+    """
+    build-deps retrieves all mandatory requirements in `requirements.txt`
+    and copies them in `pyproject.toml` dependencies list.
+    """
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-d", "--dry-run", action="store_true")
+    args = parser.parse_args()
+
+    # read and store requirements
+    requirements: list[str] = []
+    with open("requirements.txt", "r") as f:
+        for d in f.readlines():
+            d = d.replace("\n", "")
+            requirements.append(f'"{d}"')
+
+    # format requirements for pryproject.toml
+    deps: str = "dependencies = ["
+    deps += "\n" if len(requirements) >= 1 else ""
+    for dep in requirements:
+        deps += f"\t{dep},\n"
+    deps += "]"
+
+    # get and replace the pyproject.toml content
+    content: str = ""
+    with open(PYPROJECT_FILENAME, "r") as f:
+        content = f.read()
+    content = re.sub(DEPS_REGEX, deps, content, 1)
+
+    # write the new content in a temp file
+    with open(f"{PYPROJECT_FILENAME}.tmp", "w") as f:
+        f.write(content)
+
+    # if not dry run, override the original pyproject.toml
+    if not args.dry_run:
+        try:
+            os.rename(f"{PYPROJECT_FILENAME}.tmp", PYPROJECT_FILENAME)
+        except Exception as e:
+            print(f"error occurred while overriding pyproject file: {e}")
+            os.remove(f"{PYPROJECT_FILENAME}.tmp")
diff --git a/pyproject.toml b/pyproject.toml
index 45a2452..b6c38fa 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,9 @@ build-backend = "hatchling.build"
 name = "optimg"
 dynamic = ["version"]
 description = "Optimize JPEG and PNG files from a directory."
-dependencies = []
+dependencies = [
+	"tqdm==4.67.1",
+]
 
 [project.scripts]
 optimg = "optimg.__main__:main"
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..c1b8f73
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+tqdm==4.67.1
\ No newline at end of file
diff --git a/src/__main__.py b/src/__main__.py
index dab2660..2c21291 100644
--- a/src/__main__.py
+++ b/src/__main__.py
@@ -113,7 +113,7 @@ def main():
     try:
         result = optimizer.optimize(fg)
     except KeyboardInterrupt:
-        logging.info("optimizer stopped gracefully")
+        logging.error("oops, you stopped the optimizer abrutly...")
         exit(0)
     except Exception as e:
         logging.fatal(
diff --git a/src/optimizer.py b/src/optimizer.py
index 4b19a77..a34c925 100644
--- a/src/optimizer.py
+++ b/src/optimizer.py
@@ -3,10 +3,12 @@ import os
 import signal
 import subprocess
 import time
-from concurrent.futures import ProcessPoolExecutor
+from concurrent.futures import ProcessPoolExecutor, as_completed
 from dataclasses import dataclass
 from typing import Optional
 
+from tqdm import tqdm
+
 from .files import File, FileGroup, FileImgMimetype
 
 __all__ = ["ImgOptimizer", "OptimizerResult"]
@@ -33,7 +35,7 @@ def _jpeg_optim(dest_dir: str, file: File) -> tuple["File", Optional["File"]] |
     try:
         _ = subprocess.run(cmd, shell=True, check=True)
     except subprocess.CalledProcessError as e:
-        logging.error("error while running command: %s, err: %s", cmd, e.output)
+        logging.error("error while running command: %s, err: %s", cmd, e.stderr or "?")
         return None
     except Exception:
         logging.error("unexpected error while running command: %s", cmd, exc_info=True)
@@ -130,20 +132,22 @@ class ImgOptimizer:
                 p.submit(_optim, self.dest_dir, f) for f in file_group.get_files()
             ]
 
-        file_group_optim = FileGroup()
-        optimized = 0
-        for f in futures:
-            if (res := f.result()) and res is not None:
-                match res:
-                    case (orig, None):
-                        logging.debug(f"no optimization for file: {orig}")
-                        file_group_optim.add(orig)
-                    case (orig, opti):
-                        optimized += 1
-                        logging.debug(
-                            f"optimization for file: {orig} -> {(1 - (opti.size / orig.size)) * 100:.2f}%"  # noqa
-                        )
-                        file_group_optim.add(opti)
+            file_group_optim = FileGroup()
+            optimized = 0
+            for f in tqdm(
+                as_completed(futures), total=len(futures), desc="Optimizing..."
+            ):
+                if (res := f.result()) and res is not None:
+                    match res:
+                        case (orig, None):
+                            logging.debug(f"no optimization for file: {orig}")
+                            file_group_optim.add(orig)
+                        case (orig, opti):
+                            optimized += 1
+                            logging.debug(
+                                f"optimization for file: {orig} -> {(1 - (opti.size / orig.size)) * 100:.2f}%"  # noqa
+                            )
+                            file_group_optim.add(opti)
 
         logging.info(f"optimization finished in {time.perf_counter() - start:.2f}s")
         return OptimizerResult(file_group, file_group_optim, optimized)