How to write shell script for finding number of pages in PDF?

Question

I am generating a PDF dynamically. How can I check the number of pages in the PDF using a shell script?

Answer 1

Without any extra package:

strings < file.pdf | sed -n 's|.*/Count -\{0,1\}\([0-9]\{1,\}\).*|\1|p' \
    | sort -rn | head -n 1

Using pdfinfo:

pdfinfo file.pdf | awk '/^Pages:/ {print $2}'

Using pdftk:

pdftk file.pdf dump_data | grep NumberOfPages | awk '{print $2}'

---

You can also recursively sum the total number of pages in all PDFs via pdfinfo as follows:

find . -xdev -type f -name "*.pdf" -exec pdfinfo "{}" ";" | \
    awk '/^Pages:/ {n += $2} END {print n}'

Answer 2

The imagemagick library provides a tool called identify which in conjunction with counting the lines of output gets you what you are after...imagemagick is a easy install on osx with brew.

Here is a functional bash script that captures it to a shell variable and dumps it back to the screen...

#/bin/bash
pdfFile=$1
echo "Processing $pdfFile"
numberOfPages=$(/usr/local/bin/identify "$pdfFile" 2>/dev/null | wc -l | tr -d ' ')
#Identify gets info for each page, dump stderr to dev null
#count the lines of output
#trim the whitespace from the wc -l outout
echo "The number of pages is: $numberOfPages"

And the output of running it...

$ ./countPages.sh aSampleFile.pdf 
Processing aSampleFile.pdf
The number of pages is: 2
$ 

Answer 3

The pdftotext utility converts a pdf file to text format inserting page breaks between the pages. (aka: form-feed characters $'\f' ):

NAME
       pdftotext - Portable Document Format (PDF) to text converter.

SYNOPSIS
       pdftotext [options] [PDF-file [text-file]]

DESCRIPTION
       Pdftotext converts Portable Document Format (PDF) files to plain text.

       Pdftotext  reads  the PDF file, PDF-file, and writes a text file, text-file.  If text-file is
       not specified, pdftotext converts file.pdf to file.txt.  If text-file is  ´-',  the  text  is
       sent to stdout.

There are many combinations to solve your problem, choose one of them:

1) pdftotext + grep:

$ pdftotext file.pdf - | grep -c $'\f'

2) pdftotext + awk (v1):

$ pdftotext file.pdf - | awk 'BEGIN{n=0} {if(index($0,"\f")){n++}} END{print n}'

3) pdftotext + awk (v2):

$ pdftotext sample.pdf - | awk 'BEGIN{ RS="\f" } END{ print NR }'

4) pdftotext + awk (v3):

$ pdftotext sample.pdf - | awk -v RS="\f" 'END{ print NR }'

Hope it Helps!

Answer 4

Here is a version for the command line directly (based on pdfinfo):

for f in *.pdf; do pdfinfo "$f" | grep Pages | awk '{print $2}'; done

Answer 5

Here is a total hack using pdftoppm, which comes preinstalled on Ubuntu (tested on Ubuntu 18.04 and 20.04 at least):

# for a pdf withOUT a password
pdftoppm mypdf.pdf -f 1000000 2>&1 | grep -o '([0-9]*)\.$' \
| grep -o '[0-9]*'

# for a pdf WITH a password which is `1234`
pdftoppm -upw 1234 mypdf.pdf -f 1000000 2>&1 | grep -o '([0-9]*)\.$' \
| grep -o '[0-9]*'

How does this work? Well, if you specify a first page which is larger than the pages in the PDF (I specify page number 1000000, which is too large for all known PDFs), it will print the following error to stderr:

Wrong page range given: the first page (1000000) can not be after the last page (142).

So, I pipe that stderr msg to stdout with 2>&1, as explained here, then I pipe that to grep to match the (142). part with this regular expression (([0-9]*)\.$), then I pipe that to grep again with this regular expression ([0-9]*) to find just the number, which is 142 in this case. That's it!

Wrapper functions and speed testing

Here are a couple wrapper functions to test these:

# get the total number of pages in a PDF; technique 1.
# See this ans here: https://stackoverflow.com/a/14736593/4561887
# Usage (works on ALL PDFs--whether password-protected or not!):
#       num_pgs="$(getNumPgsInPdf "path/to/mypdf.pdf")"
# SUPER SLOW! Putting `time` just in front of the `strings` cmd shows it takes ~0.200 sec on a 142
# pg PDF!
getNumPgsInPdf() {
    _pdf="$1"

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

    echo "$_num_pgs"
}

# get the total number of pages in a PDF; technique 2.
# See my ans here: https://stackoverflow.com/a/66963293/4561887
# Usage, where `pw` is some password, if the PDF is password-protected (leave this off for PDFs
# with no password):
#       num_pgs="$(getNumPgsInPdf2 "path/to/mypdf.pdf" "pw")"
# SUPER FAST! Putting `time` just in front of the `pdftoppm` cmd shows it takes ~0.020 sec OR LESS
# on a 142 pg PDF!
getNumPgsInPdf2() {
    _pdf="$1"
    _password="$2"

    if [ -n "$_password" ]; then
        _password="-upw $_password"
    fi

    _num_pgs="$(pdftoppm $_password "$_pdf" -f 1000000 2>&1 | grep -o '([0-9]*)\.$' \
        | grep -o '[0-9]*')"

    echo "$_num_pgs"
}

Testing them with the time command in front shows that the strings one is extremely slow, taking ~0.200 sec on a 142 pg pdf, whereas the pdftoppm one is very fast, taking ~0.020 sec or less on the same pdf. The pdfinfo technique in Ocaso's answer below is also very fast--the same as the pdftoppm one.

See also

1. These awesome answers by Ocaso Protal.
2. These functions above will be used in my pdf2searchablepdf project here: https://github.com/ElectricRCAircraftGuy/PDF2SearchablePDF.

Answer 6

mupdf/mutool solution:

mutool info tmp.pdf | grep '^Pages' | cut -d ' ' -f 2

Answer 7

Just dug out an old script (in ksh) I found:

#!/usr/bin/env ksh
# Usage: pdfcount.sh file.pdf
#
# Optimally, this would be a mere:
#       pdfinfo file.pdf | grep Pages | sed 's/[^0-9]*//'

[[ "$#" != "1" ]] && {
   printf "ERROR: No file specified\n"
   exit 1
}

numpages=0
while read line; do
   num=${line/*([[:print:]])+(Count )?(-)+({1,4}(\d))*([[:print:]])/\4}
   (( num > numpages)) && numpages=$num
done < <(strings "$@" | grep "/Count")
print $numpages

Answer 8

If you're on macOS you can query pdf metadata like this:

mdls -name kMDItemNumberOfPages -raw file.pdf

as seen here https://apple.stackexchange.com/questions/225175/get-number-of-pdf-pages-in-terminal

Answer 9

Another mutool solution making better use of the options:

mutool show file.pdf Root/Pages/Count

Answer 10

I made a few improvement in Marius Hofert tip to sum the returned values.

for f in *.pdf; do pdfinfo "$f" | grep Pages | awk '{print $2}'; done | awk '{s+=$1}END{print s}'

Answer 11

To build on Marius Hofert's answer, this command uses a bash for loop to show you the number of pages, display the filename, and it will ignore the case of the file extension.

for f in *.[pP][dD][fF]; do pdfinfo "$f" | grep Pages | awk '{printf $2 }'; echo " $f"; done