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I need a command line tool for editing metadata of pdf-files.

I'm using a Aiptek MyNote Premium tablet for writing my notes and minutes on this device, import them later and convert them to pdf automatically with a simple script using inkscape and ghostscript.

Is there any command line tool to add some categories to the pdf's metadata, so i can find the pdf later (e.g. with gnome-do) by categories?

Update: I tried the solution with pdftk and it works, but it seems that gnome-do doesn't take care of pdf-metadata. Is there a way to get gnome-do to do that?

8 Answers 8

186

Give exiftool a try; it is available from the package libimage-exiftool-perl in the repositories.

As an example, If you have a pdf file called drawing.pdf and you want to update its metadata, use the utility, exiftool, in this way:

exiftool -Title="This is the Title" -Author="Happy Man" -Subject="PDF Metadata" drawing.pdf

For some reason the Subject entered ends up in the keywords field of the metadata in the pdf file. not a problem in some cases, even desirable, however, this may be problematic: evince and the nautilus metadata previewer do not show this, but Adobe Acrobat viewer and PDF-XChange viewer do.

The program will create a backup of the original file if you do not use the -overwrite_original switch. This means a duplicate will exist in the folder where the updated pdf is. From the example above, a file named drawing.pdf_original will be created.

Use the overwrite switch at your own risk. My suggestion is not to use it and script something to move this file to a better location just in case.

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  • 42
    Note that: "All metadata edits are reversible. While this would normally be considered an advantage, it is a potential security problem because old information is never actually deleted from the file." Aug 12, 2014 at 7:11
  • 10
    @nuttyaboutnatty if you want to purge all remnant and unused metadata entries, you can linearize the PDF file right after processing it with exiftool. This is described in more detail in this Github gist. Aug 13, 2014 at 23:41
  • 13
    @nuttyaboutnatty Well, of course it's not an authoritative source but that's only because nobody ever took the time to write one. However, I can assure that the method described by the author works. Try it out yourself: 1.) Take a PDF that has some tags and "delete" all metadata with exiftool -overwrite_original -all:all="" file.pdf; 2.) Use exiftool -PDF-update:all= file.pdf to confirm that there is still old metadata present; 3.) linearize the file with qpdf --linearize file.pdf; 4.) Check again, like you did in 2.); all metadata should be gone; Aug 14, 2014 at 7:54
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    5.) confirm that the file has been purged of all metadata by looking at the PDF dictionary (pdfinfo -meta file.pdf) Aug 14, 2014 at 7:55
  • 2
    Works perfectly. I regularly want to copy the metadata from one PDF to another, in which case exiftool -overwrite_original -tagsFromFile <srcfile> <destfile> is what I need (the option -overwrite_original overwrites the original <destfile>).
    – AstroFloyd
    Apr 22, 2018 at 15:57
23

You can edit PDF metadata using pdftk. Check out the update_info (or update_info_utf8 if you need accented characters) parameter. As for data file, below is an example:

InfoKey: Title
InfoValue: Mt-Djing: multitouch DJ table
InfoKey: Subject
InfoValue: Dissertation for Master degree
InfoKey: Keywords
InfoValue: DJing, NUI, multitouch, user-centered design
InfoKey: Author
InfoValue: Pedro Lopes

(Source)

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  • 1
    Ok, this means i have to export the metadata to a textfile, edit them and reimport the textfile. Is there a way to directly set a single metadata from command-line?
    – bdr529
    Feb 22, 2011 at 6:48
  • 1
    pdftk seems to Unicode characters in the metadata. Apr 21, 2013 at 21:06
  • 1
    I had some problem using pdftk on new pdfs (newer versions are encrypted via AESV2). Seems like it's discontinued. exiftool was working better.
    – s1lv3r
    Aug 26, 2013 at 14:58
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    to use pdftk, what you need to do is: 1) pdftk book.pdf dump_data output report.txt 2) edit report.txt 3) pdftk book.pdf update_info report.txt output bookcopy.pdf
    – craq
    Oct 24, 2017 at 3:02
  • 1
    @Pont seems to be working again in pdftk version 3.0.9. Feb 1, 2021 at 13:35
12

Using Ghostview

Install ghostscript with:

$ sudo apt install ghostscript

Create a file named pdfmarks with similar content:

[ /Title (Document title)
  /Author (Author name)
  /Subject (Subject description)
  /Keywords (comma, separated, keywords)
  /ModDate (D:20061204092842)
  /CreationDate (D:20061204092842)
  /Creator (application name or creator note)
  /Producer (PDF producer name or note)
  /DOCINFO pdfmark

then combine this pdfmarks file with a PDF, PS or EPS input file:

gs -dSAFER -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=output.pdf original.pdf pdfmarks

Source: http://milan.kupcevic.net/ghostscript-ps-pdf/

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9

To elaborate on the pdftk method, which is nice because it shows you everything that's being set, at the same time as allowing you to change anything you like, here is a script (for your .bashrc or other aliases file) to do it with one command. This creates a new version of the file you want to edit, opens your favourite editor with the metadatafile, and then implements your changes and sets the file creation/modification time on the modified PDF file to be the same as the original. To use it, after resourcing your .bashrc file, just type

editPDFmetadata myfile.pdf

Here's the alias:

editPDFmetadata() {
OUTPUT="${1}-new.pdf"
METADATA="tmp${1}-report.txt"
pdftk "${1}" dump_data output "$METADATA"
$EDITOR "$METADATA"
pdftk "${1}" update_info "$METADATA"  output "$OUTPUT"
touch -r "${1}" "${OUTPUT}"
}

Simply place the definition above into the .bashrc file in your home folder, then open a new terminal and it will be ready to use.

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    This is excellent, but I recommend quoting your variables when using them (e.g.: pdftk "${1}" dump_data ...) in case of PDF files with spaces or other special characters in their filename. Mar 16, 2020 at 2:55
  • @NiayeshIsky Thanks! Done. Hopefully the filename does not have quotes in it?
    – CPBL
    Mar 17, 2020 at 3:03
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    Thanks! About quotes: Not in my case, at least :) (Sorry - I just noticed there is one $METADATA that is still unquoted, on the second pdftk line. I don't know if AU will allow such a small edit though.) Mar 18, 2020 at 5:36
7

I needed to blank out the Author field in a PDF exported from LibreOffice. None of the solutions listed above worked for me, so I used hexedit and overwrote the Author field. Blunt instrument but effective!

In detail:

  1. Run:

    $ hexedit file.pdf
    
  2. Tab to switch to ASCII.

  3. Ctrl+S to search for "Author".

  4. Skip the <FEFF at the start of the field.

  5. Write 0 over all characters (except I preserved three 0x03 characters... YMMV) up to the closing >.

  6. Ctrl+X to save and exit.

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  • Smartest solution of them all, other solutions only work for simple mods
    – MitchellK
    Dec 22, 2021 at 13:15
6

I have extensively tested the functionality of pdftk and exiftool. I have used exiftool both at command line and through a graphical window. These have been tested for small, medium size and very large PDF documents and found to have issues with the largest and most complex PDF documents. In my experience, the pdftk / exiftool have top functionality only for small and for simple-in-formatting PDF documents. For large and complex PDF documents (eg more than 80 pages with multiple fonts) images and/or characters may fall out from the last pages after the metadata has been edited. The solution may be in the use of Ghostview, which I saw just now. No doubt these programs will improve with time.

In the meantime, I have found a solution in using the present form of Wine in Ubuntu with a one-window tiny freeware program, which works also for these large, complex PDF documents: BeCyPDFMetaEdit (available eg from freeware libraries like SoftPedia).

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4

Another command is ebook-meta (avaiable after installing Calibre).

To see tags:

ebook-meta file.pdf

To change title:

ebook-meta file.pdf -t "Conversations with Ambrosius"
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  • Neat! I like that it handles --date="1986 Feb 1" and converts it into the format PDFs use internally, whereas exiftool required me to use --CreateDate="1986:02:01 12:00:00Z". Unfortunately, ebook-meta's --date option changes neither the creation date nor the modification date in the PDF. Also, it has nothing like exiftool's "-preserve" option to preserve the file's modification timestamp.
    – hackerb9
    Jul 12, 2023 at 7:33
  • How would one go setting Producer and Creator to separate values? Feb 22 at 19:19
1

This is in the act library so you can edit PDF metadata from the command-line here as well.

$ npm install @lancejpollard/act -g
$ act update input.pdf --title foo --author bar --subject baz -k one -k two

You can also set -p publisher, -c creator, -t0 created date, and -tn updated date.

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