gs pdf tiff for multiple pages

[Vu Pham]

I use the following command to convert a pdf file to a tiff file:

#gs -q -dNOPAUSE -dBATCH -sDEVICE=tiffg4 
-sOutputFile=/home/vu/test/b.tif  /home/vu/test/b.pdf

This command converts only the first page of the pdf.

I can use %d in the output file to have multiple output files, each for 
one page of the Pdf:
#gs -q -dNOPAUSE -dBATCH -sDEVICE=tiffg4 
-sOutputFile=/home/vu/test/b%4.tif  /home/vu/test/b.pdf

but I need the output to be one file with multiple pages.

Can I do it with gs ?

Is there any command line tool out there other than gs to do this job ?

Thanks,
Vu