pdftk input.pdf cat 2-4 7 9-10 output output.pdf
pdftk
is the PDF Toolkit
input.pdf
is the input file.
cat 2-4 7 9-10
concatenate (combine) pages 2,3,4,7,9,10 of input.pdf.
output output.pdf
the resulting pdf file containing the above pages.
ps2pdf -dFirstPage=3 -dLastPage=10 input.pdf output.pdf