pdf2isbn

#!/usr/bin/env sh
#: Extract the ISBN from a PDF.
#:
#: Usage:
#:
#:    pdf2doi [filename]
#:
#: If no filename is specified, read from stdin.
#:
#: Requirements: pdfinfo (install poppler_utils), pdftotext (install xpdf or python's pdftotext).

method1() {
  pdfinfo $1 | sed -n 's/.*ISBN:* *\([0-9\-]\+\)/\1/Ip'
}

method2() {
  pdfinfo -meta $1 | sed -n 's/.*>ISBN:* *\(.*\)<.*/\1/p'
}

method3() {
  pdftotext -l 10 $1 - | sed -n 's/.*isbn/ISBN/ip'
}

method4() {
  pdftotext -l 10 $1 - | sed -n 's/.*\(978\)/\1/ip'
}

method5() {
  pdftotext -l 10 $1 - | sed -n 's/.*0-/0-/ip'
}

ISBN=$(method1 $1)

if [ -z "${ISBN}" ]; then
    # echo "Trying method 2 for $1"
    ISBN=$(method2 $1)
fi

if [ -z "${ISBN}" ]; then
    # echo "Trying method 3 for $1"
    ISBN=$(method3 $1)
fi

if [ -z "${ISBN}" ]; then
    # echo "Trying method 4 for $1"
    ISBN=$(method4 $1)
fi

if [ -z "${ISBN}" ]; then
    # echo "Trying method 5 for $1"
    ISBN=$(method4 $1)
fi

if [ -z "${ISBN}" ]; then
    ISBN=???
fi

echo "ISBN for $1 is ${ISBN}"