Reference
A sorter is a string of one of the following forms:
file header state tag:<tag> property:<property-name> property-as-time:<property-name> timestamp:<timestamp-name> reverse:<sorter> (<sorter> then <sorter>)
Examples
Sort by filename:
file
Sort by whether the entry has the 'home' tag:
tag:home
Sort by the string-representation of the value of the 'effort' property:
property:effort
Sort by the time-representation of the value of the 'timewindow' property:
property-as-time:timewindow
Sort by the BEGIN timestamp:
timestamp:BEGIN
Sort by filename, in reverse:
reverse:file
Sort by filename, then by the 'effort' property:
(file then property:effort)