This is the command for entering filters to be passed to EXTRACT. Each filter command builds on the list set up by the previous ones. For all the filter commands, a file name proceeded by a - indicates that that file should be removed from the list.
There are five filter_what values (besides quit), INTENSITY, TIME, REGION and PHA and PHASE, which will be treated in their own subheadings.
Syntax:
xsel > filter <filter_what>