merge pdfs together

merge.coffee

fs = require 'fs'
path = require 'path'
async = require 'async'
{ exec } = require 'child_process'

outs = []

async.each ( file for file in fs.readdirSync('.') when path.extname(file) is '.pdf' ), (file, cb) ->
    outs.push out = path.basename(file, '.pdf') + 'decrypted.pdf'
    exec "qpdf #{file} #{out} --decrypt", cb
, (err) ->
    outs.sort (a,b) -> parseInt(a) - parseInt(b)   
    exec "pdfunite #{outs.join(' ')} out.pdf", ->
        console.log 'done'