dpkg-awk  [(-f|--file)  filename]  [(-d|--debug) ##] [(-s|--sort) list] [(-rs|--rec_sep) ??] '<fieldname>:<regex>' ... -- <out_fieldname> ..

dpkg-awk -s Installed-Size "Status: .* installed$" -- Package Installed-Size

dpkg-awk - Utility to read a dpkg style db file

dpkg-awk Parses a dpkg status file(or other simularly formated file) and outputs the resulting records. It can use regex on the field values to limit the returned records, and it can also be told which fields to output. As another option, it can sort the matched fields.