sudo apt-get install gscan2pdf

#!/bin/bash
#scan2PDF
#Requires:      tesseract 3.03 for OCR to PDF
#               scanimage for scanning, I use  1.0.24
#               pdfunite to merge multiple PDF into one, I use 0.26.5
#
#       Use scanimage -L to get a list of devices.
#       e.g. device `genesys:libusb:006:003' is a Canon LiDE 210 flatbed scanner
#       then copy/paste genesys:libusb:006:003 into SCANNER below.
#       play with CONTRAST to get good images
DPI=300
TESS_LANG=nor  #Language that Tesseract uses for OCR
SCANNER=genesys:libusb:006:003  #My USB scanner
CONTRAST=35   #Contrast to remove paper look

FILENAME=$1 #Agrument 1,filename
PAGES=$2    #Argument 2, number of pages

re='^[0-9]+$'  #Check if second argument is a number
if ! [[ ${PAGES} =~ $re ]] ; then
   echo "error: Usage: $0 filename number_of_pages" >&2; exit 1
fi

SCRIPT_NAME=`basename "$0" .sh` #Directory to store temporary files
TMP_DIR=${SCRIPT_NAME}-tmp

if [ -d ${TMP_DIR} ]  #Check if it exists a directory already
then
        echo Error: The directory ${TMP_DIR} exists.
        exit 2
fi
mkdir ${TMP_DIR}  #Make and go to temp dir
cd ${TMP_DIR}

echo Starts Scanimage...
scanimage -d ${SCANNER} --format=tiff --mode Color --resolution ${DPI} -p --contrast ${CONTRAST} --batch-start=1 --batch-count=${PAGES}  --batch-prompt


echo Starts Tesseract OCR

for file in  *.tif  #Goes through every tif file in temp dir
do
        tesseract $file  ${file%.tif} -l ${TESS_LANG} pdf

done

if [ "$PAGES" = "1" ] #How many pages
then
    cp out1.pdf ../${FILENAME}.pdf  #Only one page, just copy the PDF back
else
        for file in *.pdf  #More pages, merge the pages into one PDF and copy back
    do
            pdfuniteargs+=${file}
            pdfuniteargs+=" "
    done
    pdfunite $pdfuniteargs ../${FILENAME}.pdf
fi
    echo ${FILENAME}.pdf done

rm *                    #Done, clean up
cd ..
rmdir ${TMP_DIR}