improve README; add google-authenticator-exporter link

README.md

@@ -15,7 +15,7 @@
 The Python script `extract_otp_secrets.py` extracts one time password (OTP) secrets from QR codes exported by two-factor authentication (2FA) apps such as "Google Authenticator".
 The exported QR codes from authentication apps can be read in three ways:
 
-1. Capture from the system camera using a GUI, 🆕
+1. Capture the QR codes with the system camera using a GUI, 🆕
 2. Read image files containing the QR codes, and 🆕
 3. Read text files containing the QR code data generated by third-party QR readers.
 
@@ -42,27 +42,33 @@ Detected QR codes are surrounded with a frame. The color of the frame indicates
 * Red: The QR code is detected and decoded, but could not be successfully extracted. This is the case if a QR code not containing OTP data is captured.
 * Magenta: The QR code is detected, but could not be decoded. The QR code should be presented better to the camera or another QR reader could be used.
 
+The secrets are printed by default to the console. [Set program parameters](#program-help-arguments-and-options) for other types of output, e.g. `--csv exported_secrets.csv`.
+
 ### With builtin QR decoder from image files (🆕 since version 2.0)
 
 1. Open "Google Authenticator" app on the mobile phone
-2. Export the QR codes from "Google Authenticator" app (see [how to export](#how-to-export-otp-secrets-from-Google-Authenticator))
+2. Export the QR codes from "Google Authenticator" app (see [how to export](#how-to-export-otp-secrets-from-google-authenticator-app))
 4. Save the QR code as image file, e.g. example_export.png
 5. Transfer the images files to the computer where his script is installed.
 6. Call this script with the file as input:
 
     python src/extract_otp_secrets.py example_export.png
 
+7. Remove unencrypted files with secrets from your computer and mobile.
+
 ### With external QR decoder app from text files
 
 1. Open "Google Authenticator" app on the mobile phone
-2. Export the QR codes from "Google Authenticator" app (see [how to export](#how-to-export-otp-secrets-from-Google-Authenticator))
+2. Export the QR codes from "Google Authenticator" app (see [how to export](#how-to-export-otp-secrets-from-google-authenticator-app))
 3. Read QR codes with a third-party QR code reader (e.g. from another phone)
-4. Save the captured QR codes from the QR code reader to a text file, e.g. example_export.txt. Save each QR code on a new line. (The captured QR codes look like `otpauth-migration://offline?data=...`)
+4. Save the captured QR codes from the QR code reader to a text file, e.g. example_export.txt. Save each QR code on a new line. (The captured QR codes look like `otpauth-migration://offline?data=…`)
 5. Transfer the file to the computer where his script is installed.
 6. Call this script with the file as input:
 
     python src/extract_otp_secrets.py example_export.txt
 
+7. Remove unencrypted files with secrets from your computer and mobile.
+
 ## Installation
 
 ```
@@ -82,7 +88,7 @@ If you do not use the `ZBAR` QR reader, you do not need to install the zbar shar
 
 For a detailed installation documentation of [pyzbar](https://github.com/NaturalHistoryMuseum/pyzbar#installation).
 
-#### Linux (Debian, Ubuntu, ...)
+#### Linux (Debian, Ubuntu, …)
 
     sudo apt-get install libzbar0
 
@@ -104,7 +110,7 @@ For a detailed installation documentation of [pyzbar](https://github.com/Natural
 
 The zbar DLLs are included with the Windows Python wheels. However, you might need additionally to install [Visual C++ Redistributable Packages for Visual Studio 2013](https://www.microsoft.com/en-US/download/details.aspx?id=40784). Install `vcredist_x64.exe` if using 64-bit Python, `vcredist_x86.exe` if using 32-bit Python. For more information see [pyzbar](https://github.com/NaturalHistoryMuseum/pyzbar)
 
-##### OpenCV
+##### OpenCV (CV2)
 
 OpenCV requires [Visual C++ redistributable 2015](https://www.microsoft.com/en-us/download/details.aspx?id=48145). For more information see [opencv-python](https://pypi.org/project/opencv-python/)
 
@@ -152,6 +158,14 @@ python extract_otp_secrets.py = < example_export.png</pre>
 
     python src/extract_otp_secrets.py example_export.png
 
+### Writing otp secrets to csv file
+
+    python src/extract_otp_secrets.py -q --csv extracted_secrets.csv example_export.txt
+
+### Writing otp secrets to json file
+
+    python src/extract_otp_secrets.py -q --json extracted_secrets.json example_export.txt
+
 ### Printing otp secrets multiple files
 
     python src/extract_otp_secrets.py example_*.txt
@@ -518,7 +532,7 @@ Options:
 
 ## Technical background
 
-The export QR code of "Google Authenticator" contains the URL `otpauth-migration://offline?data=...`.
+The export QR code of "Google Authenticator" contains the URL `otpauth-migration://offline?data=…`.
 The data parameter is a base64 encoded proto3 message (Google Protocol Buffers).
 
 Command for regeneration of Python code from proto3 message definition file (only necessary in case of changes of the proto3 message definition or new protobuf versions):
@@ -574,6 +588,7 @@ FileNotFoundError: Could not find module 'libiconv.dll' (or one of its dependenc
 * [OpenCV](https://docs.opencv.org/4.x/) (CV2) Open Source Computer Vision library with [opencv-python](https://github.com/opencv/opencv-python)
 * [Python QReader](https://github.com/Eric-Canas/QReader) Python QR code readers
 * [Android OTP Extractor](https://github.com/puddly/android-otp-extractor) can extract your tokens from popular Android OTP apps and export them in a standard format or just display them as QR codes for easy importing. [Requires a _rooted_ Android phone.]
+* [Google Authenticator secret extractor](https://github.com/krissrex/google-authenticator-exporter) is similar project written in JavaScript. It also extracts otp secrets from Google Authenticator.
 
 ***