Split PDF into multiple with n number of pages each

The following Linux shell script splits the source PDF file into multiple files with n pages of each. Totall no of pages in given input file calculated automatically and user needs to give the pages wants in each output file. This can be configured using the variable step. Default it splits the files with 5 pages.

#!/bin/bash
file="src/test.pdf";
#count total no of pages in the file
total_pages=$(pdfinfo $file | grep Pages | awk '{print $2}')
from=1
#step defines how many pages should be in output files
step=5;
while [ $from -lt $total_pages ]
do
        to=$((from+step-1));
        if [ $to -gt $total_pages ]; then
                to=$total_pages;
        fi
        echo "Generating pdf file : pages-$from-$to.pdf...";
        pdftk $file cat $from-$to output "test-$from.pdf";
        from=$((to+1));
        echo "Done.";
done