From b4edd6d2a24cbcea3fbe311d697a03a8eecf69f0 Mon Sep 17 00:00:00 2001
From: jvoisin <julien.voisin@dustri.org>
Date: Mon, 9 Jul 2018 00:17:59 +0200
Subject: [PATCH] Document that MAT2 not being able to detect metadata doesn't
mean that the file is clean
---
README.md | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/README.md b/README.md
index a29c46a..caf2aaf 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ $ python3 -m unittest discover -v
# How to use MAT2
```bash
-usage: mat2 [-h] [-v] [-l] [-c | -s | -L] [files [files ...]]
+usage: mat2 [-h] [-v] [-l] [-s | -L] [files [files ...]]
Metadata anonymisation toolkit 2
@@ -55,15 +55,24 @@ optional arguments:
-h, --help show this help message and exit
-v, --version show program's version number and exit
-l, --list list all supported fileformats
- -c, --check check if a file is free of harmful metadatas
-s, --show list all the harmful metadata of a file without removing
them
-L, --lightweight remove SOME metadata
```
+# Notes about detecting metadata
+
+While MAT2 is doing its very best to display metadata when the `--show` flag is
+passed, it doesn't mean that a file is clean from any metadata if MAT2 doesn't
+show any. There is no reliable way to detect every single possible metadata for
+complex file formats.
+
+This is why you shouldn't rely on metadata's presence to decide if your file must
+be cleaned or not.
+
# Related software
-- The first iteration of [MAT](http://mat.boum.org)
+- The first iteration of [MAT](https://mat.boum.org)
- [Exiftool](https://sno.phy.queensu.ca/~phil/exiftool/mat)
- [pdf-redact-tools](https://github.com/firstlookmedia/pdf-redact-tools), that
tries to deal with *printer dots* too.
--
GitLab