The usual techniques with UNIX tools such as grep, gawk (awk) are available for extracting subdatabases. Tools for reconstituting input database formats for the specific attributes are not provided at the moment, but the techniques used in the tools provided can be examined and used for this purpose. One special purpose tool, dbselect, is provided for extracting subdatabases by attribute name.
The instruction
dbselect sfb.lex Orth A3 B1 C1 D1generates a subdatabase containing only the attributes Orth A3 B1 C1 D1 in file "sfb.lex" No example is provided, as the output would be as long as the database (currently 2078 entries).