#! /bin/sh

# grep a value of a CIF-like tag; take into account values that are on
# the next line an that may span several lines

PATTERN="$1"
shift

awk "/${PATTERN}/ {
        print
        if( NF == 1 ) {
            getline; print
        }
        if( match( \$0, \"^;\" )) {
            getline; print;
            while( !match( \$0, \"^;\" )) {
                getline; print
            }
        }
}" ${1+"$@"}