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3.2 Selecting by Type

As we saw in the section discussing record descriptors, it is possible to have several different types of records in a single recfile. Consider for example a gnu.rec file containing information about maintainers and packages in the GNU Project:

%rec: Maintainer

Name: Jose E. Marchesi
Email: jemarch@gnu.org

Name: Luca Saiu 
Email: positron@gnu.org

%rec: Package

Name: GNU recutils
LastRelease: 12 February 2014

Name: GNU epsilon
LastRelease: 10 March 2013

If recsel is invoked in that file it will complain:

$ recsel gnu.rec
recsel: error: several record types found.  Please use -t to specify one.

This is because recsel does not know which records to output: the maintainers or the packages. This can be resolved by using the -t command line option:

$ recsel -t Package gnu.rec
Name: GNU recutils
LastRelease: 12 February 2014

Name: GNU epsilon
LastRelease: 10 March 2013

By default recsel never outputs record descriptors. This is because most of the time the user is only interested in the data. However, with the -d command line option, the record descriptor of the selected type is printed preceding the data records:

$ recsel -d -t Maintainer gnu.rec
%rec: Maintainer

Name: Jose E. Marchesi
Email: jemarch@gnu.org

Name: Luca Saiu 
Email: positron@gnu.org

Note that at the moment it is not possible to select non-typed (default) records when other record sets are stored in the same file. This is one of the reasons why mixing non-typed records and typed records in a single recfile is not recommended.

Note also that if a nonexistent record type is specified in -t then recsel does nothing.


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