A sink file contains meta information, as well as, potentially a lot of, padding. This can be removed by the vacuum_sink command that uses the sink files meta information to produce an aggregated output file that contains only the actual data produced by each of the individual processes.

vacuum_sink  -sink_file data.sink  -out_file data.txt

As mentioned, the data need not be text data, it can be binary data as well, but in that case vacuum_sink my not be the correct approach.

Optionally, vacuum_sink can produce feedback useful for tuning and/or debugging. The -verbose flag allows to set the level of information printed to standard error. For level 0 there is no feedback, level ` provides run time information, higher levels may be added in future.

Help on the avaible command line options for this command can be obtained using the -? flag.