Splitting a PDF with Ghostscript

 #!/bin/bash
#where $1 is the input filename

ournum=`gs -q -dNODISPLAY -c "("$1") (r) file runpdfbegin pdfpagecount = quit" 2>/dev/null`
echo "Processing $ournum pages"
counter=1
while [ $counter -le $ournum ] ; do
    newname=`echo $1 | sed -e s/\.pdf//g`
    reallynewname=$newname-$counter.pdf
    counterplus=$((counter+1))
    # make the individual pdf page
    yes | gs -dBATCH -sOutputFile="$reallynewname" -dFirstPage=$counter -dLastPage=$counter -sDEVICE=pdfwrite "$1" >& /dev/null
    counter=$counterplus
done

I found this script wriiten by Mr Weimer super useful:

#!/bin/sh
#
# pdfsplit [input.pdf] [first_page] [last_page] [output.pdf] 
#
# Example: pdfsplit big_file.pdf 10 20 pages_ten_to_twenty.pdf
#
# written by: Westley Weimer, Wed Mar 19 17:58:09 EDT 2008
#
# The trick: ghostscript (gs) will do PDF splitting for you, it's just not
# obvious and the required defines are not listed in the manual page. 

if [ $# -lt 4 ] 
then
        echo "Usage: pdfsplit input.pdf first_page last_page output.pdf"
        exit 1
fi
gs -dNOPAUSE -dQUIET -dBATCH -sOutputFile="$4" -dFirstPage=$2 -dLastPage=$3 -sDEVICE=pdfwrite "$1"

Origin from : http://www.cs.virginia.edu/~weimer/pdfsplit/pdfsplit

save it as pdfsplit.sh, see the magic happens.

PDFSAM also could do the job. Available on Windows and Mac.

What you see is "normal" behaviour: the current version of Ghostscript's pdfwrite output device does not support this feature. This is also (admittedly, somehow vaguely) documented in Use.htm:

"Note, however that the one page per file feature may not be supported by all devices...."

I seem to remember that one of the Ghostscript developers mentioned on IRC that they may add this feature to pdfwrite in some future release, but it seems to necessitate some major code rewrite, which is why they haven't done it yet...

---

Update: As Gordon's comment already hinted at, as of version 9.06 (released on July 31st, 2012), Ghostscript now supports the commandline as quoted in the question also for pdfwrite. (Gordon must have discovered the unofficial support for this already in 9.05, or he compiled his own executable from the pre-release sources which were not yet tagged as 9.06).