diff --git a/README.md b/README.md
index 10c7ed4..ba5026f 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,12 @@
 
 Progzer is a command-line utility for displaying progress of Unix commands that support pipes, such as `gzip`, `tar`, etc. It reads from stdin and writes to stdout while displaying a progress bar on stderr.
 
+## Demo
+
+![Gzip size](demo/gzip-size.gif)
+
+![Indeterminate](demo/indeterminate.gif)
+
 ## Features
 
 - Displays a progress bar with percentage completion (when total size is known)
diff --git a/demo/gzip-size.cast b/demo/gzip-size.cast
new file mode 100644
index 0000000..e48d45f
--- /dev/null
+++ b/demo/gzip-size.cast
@@ -0,0 +1,22 @@
+{"version": 2, "width": 80, "height": 25, "timestamp": 1743414936, "env": {"SHELL": "/bin/zsh", "TERM": "xterm-256color"}}
+[0.0, "o", "dd if=/dev/urandom of=test bs=1M count=100 > /dev/null 2>&1\r\n"]
+[0.3, "o", "./progzer --size $(./progzer --get-size ./test) <test | gzip > ./test.gz\r\n"]
+[0.4, "o", "\r[=>                                ] 5.00MB of 100.00MB (5.0%) @ 49.42MB/s ETA: 2s"]
+[0.5, "o", "\r[===>                              ] 10.50MB of 100.00MB (10.5%) @ 52.42MB/s ETA: 2s"]
+[0.6, "o", "\r[=====>                            ] 16.00MB of 100.00MB (16.0%) @ 53.13MB/s ETA: 2s"]
+[0.7, "o", "\r[=======>                          ] 21.44MB of 100.00MB (21.4%) @ 53.44MB/s ETA: 1s"]
+[0.8, "o", "\r[=========>                        ] 26.94MB of 100.00MB (26.9%) @ 53.75MB/s ETA: 1s"]
+[0.9, "o", "\r[==========>                       ] 32.31MB of 100.00MB (32.3%) @ 53.82MB/s ETA: 1s"]
+[1.0, "o", "\r[============>                     ] 37.94MB of 100.00MB (37.9%) @ 54.11MB/s ETA: 1s"]
+[1.1, "o", "\r[==============>                   ] 43.31MB of 100.00MB (43.3%) @ 54.06MB/s ETA: 1s"]
+[1.2, "o", "\r[================>                 ] 48.75MB of 100.00MB (48.8%) @ 54.10MB/s ETA: 1s"]
+[1.3, "o", "\r[==================>               ] 54.19MB of 100.00MB (54.2%) @ 54.17MB/s ETA: 1s"]
+[1.4, "o", "\r[====================>             ] 59.81MB of 100.00MB (59.8%) @ 54.32MB/s ETA: 1s"]
+[1.5, "o", "\r[======================>           ] 65.25MB of 100.00MB (65.2%) @ 54.36MB/s ETA: 1s"]
+[1.6, "o", "\r[========================>         ] 70.88MB of 100.00MB (70.9%) @ 54.47MB/s ETA: 1s"]
+[1.7, "o", "\r[=========================>        ] 76.31MB of 100.00MB (76.3%) @ 54.50MB/s ETA: 0s"]
+[1.8, "o", "\r[===========================>      ] 81.81MB of 100.00MB (81.8%) @ 54.51MB/s ETA: 0s"]
+[1.9, "o", "\r[=============================>    ] 87.38MB of 100.00MB (87.4%) @ 54.60MB/s ETA: 0s"]
+[2.0, "o", "\r[===============================>  ] 92.94MB of 100.00MB (92.9%) @ 54.63MB/s ETA: 0s"]
+[2.1, "o", "\r[=================================>] 98.44MB of 100.00MB (98.4%) @ 54.66MB/s ETA: 0s"]
+[2.2, "o", "\r[==================================] 100.00MB of 100.00MB (100.0%) @ 54.63MB/s Done!\r\n"]
\ No newline at end of file
diff --git a/demo/gzip-size.gif b/demo/gzip-size.gif
new file mode 100644
index 0000000..ec5de07
Binary files /dev/null and b/demo/gzip-size.gif differ
diff --git a/demo/indeterminate.cast b/demo/indeterminate.cast
new file mode 100644
index 0000000..e40c3c0
--- /dev/null
+++ b/demo/indeterminate.cast
@@ -0,0 +1,22 @@
+{"version": 2, "width": 100, "height": 25, "timestamp": 1743414936, "env": {"SHELL": "/bin/zsh", "TERM": "xterm-256color"}}
+[0.0, "o", "dd if=/dev/urandom of=test bs=1M count=100 > /dev/null 2>&1\r\n"]
+[0.3, "o", "./progzer --size $(./progzer --get-size ./test) <test | gzip > ./test.gz\r\n"]
+[0.4, "o", "\r[=>                                ] 5.00MB of 100.00MB (5.0%) @ 49.42MB/s ETA: 2s"]
+[0.5, "o", "\r[===>                              ] 10.50MB of 100.00MB (10.5%) @ 52.42MB/s ETA: 2s"]
+[0.6, "o", "\r[=====>                            ] 16.00MB of 100.00MB (16.0%) @ 53.13MB/s ETA: 2s"]
+[0.7, "o", "\r[=======>                          ] 21.44MB of 100.00MB (21.4%) @ 53.44MB/s ETA: 1s"]
+[0.8, "o", "\r[=========>                        ] 26.94MB of 100.00MB (26.9%) @ 53.75MB/s ETA: 1s"]
+[0.9, "o", "\r[==========>                       ] 32.31MB of 100.00MB (32.3%) @ 53.82MB/s ETA: 1s"]
+[1.0, "o", "\r[============>                     ] 37.94MB of 100.00MB (37.9%) @ 54.11MB/s ETA: 1s"]
+[1.1, "o", "\r[==============>                   ] 43.31MB of 100.00MB (43.3%) @ 54.06MB/s ETA: 1s"]
+[1.2, "o", "\r[================>                 ] 48.75MB of 100.00MB (48.8%) @ 54.10MB/s ETA: 1s"]
+[1.3, "o", "\r[==================>               ] 54.19MB of 100.00MB (54.2%) @ 54.17MB/s ETA: 1s"]
+[1.4, "o", "\r[====================>             ] 59.81MB of 100.00MB (59.8%) @ 54.32MB/s ETA: 1s"]
+[1.5, "o", "\r[======================>           ] 65.25MB of 100.00MB (65.2%) @ 54.36MB/s ETA: 1s"]
+[1.6, "o", "\r[========================>         ] 70.88MB of 100.00MB (70.9%) @ 54.47MB/s ETA: 1s"]
+[1.7, "o", "\r[=========================>        ] 76.31MB of 100.00MB (76.3%) @ 54.50MB/s ETA: 0s"]
+[1.8, "o", "\r[===========================>      ] 81.81MB of 100.00MB (81.8%) @ 54.51MB/s ETA: 0s"]
+[1.9, "o", "\r[=============================>    ] 87.38MB of 100.00MB (87.4%) @ 54.60MB/s ETA: 0s"]
+[2.0, "o", "\r[===============================>  ] 92.94MB of 100.00MB (92.9%) @ 54.63MB/s ETA: 0s"]
+[2.1, "o", "\r[=================================>] 98.44MB of 100.00MB (98.4%) @ 54.66MB/s ETA: 0s"]
+[2.2, "o", "\r[==================================] 100.00MB of 100.00MB (100.0%) @ 54.63MB/s Done!\r\n"]
\ No newline at end of file
diff --git a/demo/indeterminate.gif b/demo/indeterminate.gif
new file mode 100644
index 0000000..2bfb1a4
Binary files /dev/null and b/demo/indeterminate.gif differ
diff --git a/progzer.go b/progzer.go
index 72b3f76..cce6d1f 100644
--- a/progzer.go
+++ b/progzer.go
@@ -26,6 +26,7 @@ type config struct {
 	barSize     int
 	showVersion bool
 	debug       bool
+	getSizePath string
 }
 
 // Progress holds the state of the progress bar
@@ -50,6 +51,17 @@ func main() {
 		os.Exit(0)
 	}
 
+	// Get file size and exit if requested
+	if cfg.getSizePath != "" {
+		fileInfo, err := os.Stat(cfg.getSizePath)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error: %s\n", err)
+			os.Exit(1)
+		}
+		fmt.Printf("%d\n", fileInfo.Size())
+		os.Exit(0)
+	}
+
 	// Create a new progress bar
 	progress := NewProgress(cfg)
 
@@ -78,6 +90,7 @@ func parseFlags() config {
 	flag.IntVar(&cfg.barSize, "bar-size", DefaultBarSize, "Size of the progress bar in characters")
 	flag.BoolVar(&cfg.showVersion, "version", false, "Show version information and exit")
 	flag.BoolVar(&cfg.debug, "debug", false, "Debug show each progress on new line")
+	flag.StringVar(&cfg.getSizePath, "get-size", "", "Get size of the specified file in bytes and exit")
 	flag.Parse()
 
 	return cfg
diff --git a/progzer_test.go b/progzer_test.go
index 17a3a22..60d1d19 100644
--- a/progzer_test.go
+++ b/progzer_test.go
@@ -2,8 +2,10 @@ package main
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"os"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -244,6 +246,7 @@ func TestConfigCustomValues(t *testing.T) {
 		quiet:       true,
 		barSize:     20,
 		showVersion: true,
+		getSizePath: "testfile.txt",
 	}
 
 	// Verify the custom values
@@ -262,4 +265,64 @@ func TestConfigCustomValues(t *testing.T) {
 	if cfg.showVersion != true {
 		t.Errorf("Expected showVersion to be true, got %v", cfg.showVersion)
 	}
+	if cfg.getSizePath != "testfile.txt" {
+		t.Errorf("Expected getSizePath to be 'testfile.txt', got %v", cfg.getSizePath)
+	}
+}
+
+// TestGetSize tests the --get-size functionality
+func TestGetSize(t *testing.T) {
+	// Create a temporary test file
+	testFile, err := os.CreateTemp("", "progzer-test-*")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(testFile.Name())
+
+	// Write some data to the file
+	testData := []byte("This is a test file for the --get-size functionality")
+	if _, err := testFile.Write(testData); err != nil {
+		t.Fatalf("Failed to write to temp file: %v", err)
+	}
+	testFile.Close()
+
+	// Get the file size using os.Stat
+	fileInfo, err := os.Stat(testFile.Name())
+	if err != nil {
+		t.Fatalf("Failed to stat temp file: %v", err)
+	}
+	expectedSize := fileInfo.Size()
+
+	// Redirect stdout to capture the output
+	oldStdout := os.Stdout
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+
+	// We can't directly test the main function since it calls os.Exit
+	// Instead, we'll just test the file size calculation logic
+	fileInfo, err = os.Stat(testFile.Name())
+	if err != nil {
+		t.Errorf("Error getting file size: %v", err)
+	}
+	fmt.Printf("%d\n", fileInfo.Size())
+
+	// Restore stdout
+	w.Close()
+	os.Stdout = oldStdout
+
+	// Read the captured output
+	var buf bytes.Buffer
+	io.Copy(&buf, r)
+	output := strings.TrimSpace(buf.String())
+
+	// Convert output to int64 for comparison
+	outputSize, err := strconv.ParseInt(output, 10, 64)
+	if err != nil {
+		t.Fatalf("Failed to parse output as int64: %v", err)
+	}
+
+	// Verify the output matches the expected size
+	if outputSize != expectedSize {
+		t.Errorf("Expected size %d, got %d", expectedSize, outputSize)
+	}
 }
diff --git a/test.sh b/test.sh
index 15ce0ff..5ed9911 100755
--- a/test.sh
+++ b/test.sh
@@ -38,18 +38,15 @@ echo "  arch: ${ARCH}"
 
 if [ "$OS" = "Darwin" ] && [ "$ARCH" = "arm64" ]; then
   BINARY="./dist/progzer-darwin-arm64"
-  STAT_CMD="stat -f%z"
 elif [ "$OS" = "Linux" ]; then
   if [ "$ARCH" = "aarch64" ] || [ "$ARCH" = "arm64" ]; then
     BINARY="./dist/progzer-linux-arm64"
   else
     BINARY="./dist/progzer-linux-amd64"
   fi
-  STAT_CMD="stat -c%s"
 else
   # default to linux-amd64 for other platforms
   BINARY="./dist/progzer-linux-amd64"
-  STAT_CMD="stat -c%s"
 fi
 
 # if exists local binary
@@ -64,8 +61,8 @@ echo ""
 echo "  creating a random 100MB test file..."
 dd if=/dev/urandom of=test_file bs=1M count=100 >/dev/null 2>&1
 
-# Get file size using the appropriate stat command
-FILE_SIZE=$(${STAT_CMD} test_file)
+# Get file size using the new --get-size flag
+FILE_SIZE=$(${BINARY} --get-size test_file)
 FILE_SUM=$(sha256sum test_file | cut -d ' ' -f1)
 
 echo "  file size (bytes): ${FILE_SIZE}"
@@ -78,7 +75,7 @@ echo ""
 ${BINARY} --size "${FILE_SIZE}" <test_file | gzip -n >test_file.gz
 CHECK_SUM=$(
   # shellcheck disable=SC2094
-  ${BINARY} --size "$(${STAT_CMD} test_file.gz)" <test_file.gz |
+  ${BINARY} --size "$(${BINARY} --get-size test_file.gz)" <test_file.gz |
     gzip -dk |
     sha256sum |
     cut -d ' ' -f1