The command selects data records which produce the value TRUE when a given boolean expression is evaluated for them. Note that the result data has the same fields as the source data. Thus it must be located in a different directory. An expression must be boolean-valued. See more about expressions in Section 4.2.1.
Example (ex4.4): The example selects records which represent expensive apartments.
NDA> load boston.dat NDA> selrec -d boston -expr 'boston.rate'>30; -dout data ... # continue analysis for them NDA> prepro -d data -dout ... NDA> somtr ... ...