UPDATED 2014-12-14 — Sometimes an Evernote note is produced with invalid characters. The script below has been updated to strip out invalid characters.

Over on the Evernote forums, jonteamere said, “it’d be nice to build, within EN, a single PDF document from individual docs.”

I’ve had an itch for the same feature. It turns out that this is totally do-able in vanilla OS X. The following script grabs the currently selected notes from Evernote (in their visible sort order) and their PDF attachments, then creates a new note with a single PDF. It ignores non-PDF attachments.

-- Join PDFs in multiple Evernote notes into a single PDF in a new note
-- Author: John Christopher Jones <john.christopher@alumni.virginia.edu>
-- Created: 2014-11-17
-- Updated: 2014-12-11 -- write utf8 and strip non-ascii characters when extracting hash values

-- inspired by
-- https://discussion.evernote.com/topic/75343-feature-request-ability-to-combine-not-merge-individual-pdf-notes/?locale=en
-- https://discussion.evernote.com/topic/24388-how-to-access-note-attachments-with-applescript/
-- https://applehelpwriter.com/2013/03/23/how-to-merge-pdf-files-in-os-x/

-- We'll join note titles together using this string
-- This isn't going to be a great title, but it'll be
-- a good reminder of what's in the new note.
set title_separator to " | "

-- Create a temporary folder for the exported Evernote attachments
-- Create an output filepath to write the joined pdf to
set temp_folder to do shell script "mktemp -d -t evernote_pdf"
set output_filepath to temp_folder & "/" & (do shell script "uuidgen") & ".pdf"

-- XSLT used to extract hash values from en-media tags
-- Crazy {} translation nonsense used to work around forum post scrubbers
set xslt to "{?xml version='1.0'?}
{xsl:stylesheet version='1.0' xmlns:xsl='https://www.w3.org/1999/XSL/Transform'
                xmlns:en='https://xml.evernote.com/pub/enml2.dtd'}
    {xsl:output method='text' omit-xml-declaration='yes' indent='no'/}
    {xsl:strip-space elements='*'/}
    {xsl:template match='en-media'}
        {xsl:value-of select='@hash'/}
        {xsl:text}&#xa;{/xsl:text}
    {/xsl:template}
    {xsl:template match='text()|@*'}{/xsl:template}
{/xsl:stylesheet}
"
set my text item delimiters to "{"
set xslt to text items of xslt
set my text item delimiters to "<"
set xslt to xslt as text
set my text item delimiters to "}"
set xslt to text items of xslt
set my text item delimiters to ">"
set xslt to xslt as text

-- Write XSLT to temporary location
set xslt_path to do shell script "mktemp -t evernote_enml"
tell application "Finder" to write xslt to xslt_path

-- Initialize some lists
set hash_values to {}
set pdf_list to {}
set title_list to {}

tell application "Evernote"
    -- Loop over every attachment in every note
    -- Note order follows the visible sort order in the OS X Desktop Client v5.7.2
    set noteList to selection
    repeat with n in noteList
        set the end of title_list to title of n

        -- Write the ENML to a temporary file and extract the en-media hash values
        set enml_text to (ENML content of n) as text
        set enml_path to do shell script "mktemp -t evernote_enml"
        tell application "Finder" to write enml_text to enml_path

        -- Extract the hash values from the ENML temporary file using the XSLT
        set hash_values to paragraphs of (do shell script "cat " & (quoted form of enml_path) & " | strings | xsltproc --novalid " & (quoted form of xslt_path) & " - ")
        -- Delete the temporary ENML file
        do shell script "rm " & (quoted form of enml_path)

        -- Export each attachment in the order that it appears in the note
        repeat with hash_value in hash_values
            -- Get the attachment that has this hash
            set a to item 1 of (attachments of n whose hash is hash_value)
            -- Write the attachment to the temporary folder
            set pdf_path to temp_folder & "/" & (do shell script "uuidgen") & ".pdf"
            write a to pdf_path as «class utf8»
            -- Save the filepath for later
            set the end of pdf_list to pdf_path
        end repeat
    end repeat

    -- We'll join PDF filepaths so that they're single-quoted and space-delimited
    set my text item delimiters to "' '"

    -- Join PDFs
    do shell script (quoted form of "/System/Library/Automator/Combine PDF Pages.action/Contents/Resources/join.py") & " --output " & (quoted form of output_filepath) & " " & ("'" & (pdf_list as text) & "'")

    -- Create a new note with a title built from the titles of the selected notes
    set my text item delimiters to title_separator
    set new_note to create note from file output_filepath title (title_list as text)

    -- Open the newly created note in a new window so the user doesn't have to wonder
    -- where the thing is and if it was actually created.
    open note window with new_note

    -- Delete all of the remaining temporary files
    do shell script "rm -r " & quoted form of temp_folder
    do shell script "rm " & quoted form of xslt_path
end tell

Installation

I highly recommend Keyboard Maestro as an easy way to assign keyboard shortcuts to AppleScript scripts.

However, a free way to conveniently use this script is to activate the script menu via OS X’s Script Editor, then save the script to the Evernote scripts folder. You’ll then be able to run the script from the script menu.

Disclaimer

This script hasn’t been rigorously tested, but it works for me.

Credits

I needed to accomplish a few things with this script:

  1. pick out some Evernote notes,
  2. extract their attachments in a usable form,
  3. join the attachments, and finally
  4. create a new note and attach the joined document.

I learned from philastokes’s 2013-03-23 post that OS X comes with a bundled python script to join PDFs as part of the “Combine PDF Pages” Automator action. Back in 2012 on the Evernote forums, iNik demonstrated writing attachments from Evernote. The official Evernote AppleScript Examples showed me the rest of the Evernote-specific stuff.