missing commands
-Work in progress
+Given a set of nodes C that represent classes, compute the set of all instances of every member in C.
+
+## Usage:
+```
+kgtk instances OPTIONS
+```
+## Options:
+```
+--isa-file: the name of the isa file, if different from the default.
+--classes: identifiers of classes, comma-separated. The set of classes can be provided in the standard input or chained from the previous command in the pipeline
+```
+
+## Examples
+
+instances of the subclasses of two classes
+```
+kgtk instances --transitive --class Q13442814,Q12345678
+```
