Add README for command-line example

Author: yushulx

examples/command-line/README.md

@@ -0,0 +1,92 @@
+# Command-Line Barcode & QR Code Reader (C++)
+
+This example shows how to build and run a C++ command-line app that reads barcodes/QR codes from:
+
+- A single image/PDF/TIFF file
+- A directory (processed recursively)
+- Multiple paths passed in one command
+
+The app is implemented in [`main.cpp`](./main.cpp) and uses **Dynamsoft Capture Vision Router** with the `PT_READ_BARCODES` preset template.
+
+## Supported input formats
+
+The sample accepts these file extensions:
+
+- `.jpg`, `.jpeg`, `.png`, `.bmp`, `.gif`
+- `.tif`, `.tiff`
+- `.pdf`
+
+## Build
+
+From this folder (`examples/command-line`):
+
+```bash
+mkdir -p build
+cd build
+cmake ..
+cmake --build . --config Release
+```
+
+After building, the executable is generated in `build/`:
+
+- Linux/macOS: `./main`
+- Windows: `./Release/main.exe` (or `./main.exe` depending on generator)
+
+> During post-build steps, required Dynamsoft libraries, `Templates/`, and `Models/` are copied next to the executable automatically.
+
+## Run
+
+### 1) Process a single file
+
+```bash
+./main ../single_page.tif
+```
+
+### 2) Process a directory recursively
+
+```bash
+./main ../../images
+```
+
+### 3) Process multiple paths in one command
+
+```bash
+./main ../single_page.tif ../multi_page.tif ../../images
+```
+
+### 4) Interactive mode
+
+If no arguments are provided, the app enters interactive mode:
+
+```bash
+./main
+```
+
+Then type a full file or directory path. Enter `q` to quit.
+
+## Output behavior
+
+- **Single file**: prints detailed results (format, text, and quadrilateral points per barcode).
+- **Directory**: prints per-file summary and directory statistics.
+- **Multiple inputs**: prints per-input results and an overall summary.
+
+## License key
+
+The demo initializes a trial license in source code. For production use, replace it with your own key in `main.cpp`:
+
+```cpp
+CLicenseManager::InitLicense("LICENSE-KEY", szErrorMsg, 256);
+```
+
+Get a trial license here:
+
+- https://www.dynamsoft.com/customer/license/trialLicense/?product=dcv&package=cross-platform
+
+## Sample files in this folder
+
+- `single_page.tif`
+- `multi_page.tif`
+- `multi_page.pdf`
+- `test.pdf`
+
+You can use these files to quickly validate decoding.