note how to erase pdf metadata

data/exiftool.md

@@ -22,6 +22,7 @@ And overwrite all metadata:
 ```bash
 exiftool -all= -overwrite_original -ext jpg .
 ```
+(NB: This does not work on pdf data. See [here](pdf_erasure.md) for erasing all pdf data)
 
 Or just GPS data:
 
@@ -36,3 +37,4 @@ identify -verbose
 ```
 
 
+

data/pdf_erasure.md

@@ -0,0 +1,25 @@
+---
+title: "PDF Metadata Erasure"
+tags: [ "Documentation", "Metadata", "Ghost Script" ]
+---
+
+Make a text file called 'pdfmark.txt'.
+
+
+```text
+[ /Title ()
+/Author ()
+/Subject ()
+/Creator ()
+/ModDate ()
+/Producer ()
+/Keywords ()
+/CreationDate ()
+/DOCINFO pdfmark
+```
+
+Then run:
+
+```bash
+gs -o output.pdf -sDEVICE=pdfwrite "$FILE".pdf pdfmark.txt
+```