Get the number of pages in a PDF document

Question

This question is for referencing and comparing. The solution is the accepted answer below.

Many hours have I searched for a fast and easy, but mostly a

Answer 1

You can use qpdf like below. If a file file_name.pdf has 100 pages,

$ qpdf --show-npages file_name.pdf
100

Answer 2

If you have access to shell, a simplest (but not usable on 100% of PDFs) approach would be to use grep.

This should return just the number of pages:

grep -m 1 -aoP '(?<=\/N )\d+(?=\/)' file.pdf

Example: https://regex101.com/r/BrUTKn/1

Switches description:

• -m 1 is neccessary as some files can have more than one match of regex pattern (volonteer needed to replace this with match-only-first regex solution extension)
• -a is neccessary to treat the binary file as text
• -o to show only the match
• -P to use Perl regular expression

Regex explanation:

• starting "delimiter": (?<=\/N ) lookbehind of /N (nb. space character not seen here)
• actual result: \d+ any number of digits
• ending "delimiter": (?=\/) lookahead of /

Nota bene: if in some case match is not found, it's safe to assume only 1 page exists.

Answer 3

The R package pdftools and the function pdf_info() provides information on the number of pages in a pdf.

library(pdftools)
pdf_file <- file.path(R.home("doc"), "NEWS.pdf")
info <- pdf_info(pdf_file)
nbpages <- info[2]
nbpages

$pages
[1] 65

Answer 4

I created a wrapper class for pdfinfo in case it's useful to anyone, based on Richard's answer@

/**
 * Wrapper for pdfinfo program, part of xpdf bundle
 * http://www.xpdfreader.com/about.html
 * 
 * this will put all pdfinfo output into keyed array, then make them accessible via getValue
 */
class PDFInfoWrapper {

    const PDFINFO_CMD = 'pdfinfo';

    /**
     * keyed array to hold all the info
     */
    protected $info = array();

    /**
     * raw output in case we need it
     */
    public $raw = "";

    /**
     * Constructor
     * @param string $filePath - path to file
     */
    public function __construct($filePath) {
        exec(self::PDFINFO_CMD . ' "' . $filePath . '"', $output);

        //loop each line and split into key and value
        foreach($output as $line) {
            $colon = strpos($line, ':');
            if($colon) {
                $key = trim(substr($line, 0, $colon));
                $val = trim(substr($line, $colon + 1));

                //use strtolower to make case insensitive
                $this->info[strtolower($key)] = $val;
            }
        }

        //store the raw output
        $this->raw = implode("\n", $output);

    }

    /**
     * get a value
     * @param string $key - key name, case insensitive
     * @returns string value
     */
    public function getValue($key) {
        return @$this->info[strtolower($key)];
    }

    /**
     * list all the keys
     * @returns array of key names
     */
    public function getAllKeys() {
        return array_keys($this->info);
    }

}

Answer 5

Here is a Windows command script using gsscript that reports the PDF file page number

@echo off
echo.
rem
rem this file: getlastpagenumber.cmd
rem version 0.1 from commander 2015-11-03
rem need Ghostscript e.g. download and install from http://www.ghostscript.com/download/
rem Install path "C:\prg\ghostscript" for using the script without changes \\ and have less problems with UAC
rem

:vars
  set __gs__="C:\prg\ghostscript\bin\gswin64c.exe"
  set __lastpagenumber__=1
  set __pdffile__="%~1"
  set __pdffilename__="%~n1"
  set __datetime__=%date%%time%
  set __datetime__=%__datetime__:.=%
  set __datetime__=%__datetime__::=%
  set __datetime__=%__datetime__:,=%
  set __datetime__=%__datetime__:/=% 
  set __datetime__=%__datetime__: =% 
  set __tmpfile__="%tmp%\%~n0_%__datetime__%.tmp"

:check
  if %__pdffile__%=="" goto error1
  if not exist %__pdffile__% goto error2
  if not exist %__gs__% goto error3

:main
  %__gs__% -dBATCH -dFirstPage=9999999 -dQUIET -dNODISPLAY -dNOPAUSE  -sstdout=%__tmpfile__%  %__pdffile__%
  FOR /F " tokens=2,3* usebackq delims=:" %%A IN (`findstr /i "number" test.txt`) DO set __lastpagenumber__=%%A 
  set __lastpagenumber__=%__lastpagenumber__: =%
  if exist %__tmpfile__% del %__tmpfile__%

:output
  echo The PDF-File: %__pdffilename__% contains %__lastpagenumber__% pages
  goto end

:error1
  echo no pdf file selected
  echo usage: %~n0 PDFFILE
  goto end

:error2
  echo no pdf file found
  echo usage: %~n0 PDFFILE
  goto end

:error3
  echo.can not find the ghostscript bin file
  echo.   %__gs__%
  echo.please download it from:
  echo.   http://www.ghostscript.com/download/
  echo.and install to "C:\prg\ghostscript"
  goto end

:end
  exit /b

Answer 6

if you can't install any additional packages, you can use this simple one-liner:

foundPages=$(strings < $PDF_FILE | sed -n 's|.*Count -\{0,1\}\([0-9]\{1,\}\).*|\1|p' | sort -rn | head -n 1)