Useful Undocumented Commands

[MDSmith526]

initialize - sets up system of equations but doesn't solve
remove timeSeries $tag
nodeReaction $nodeTag <$dof> - returns a tcl list of node reactions at the "time" when this command is called
nodeResponse - like the eleResponse command, but for nodes
eleForce $eleTag <$dof> - returns a tcl list of element forces at the "time" when this command is called, looks to be specialized type of eleResponse command
eleNodes $eleTag - returns a tcl list of the nodes attached to a given element
nodeMass $nodeTag $DOF - returns the mass for the given node and DOF. To my knowledge, this is currently the most direct way to build the mass matrix.
quit - same as exit
version - returns string of version of opensees

There are a few more, but these are some I found interesting.

[maksins]

Thanks Matthew,
I was not aware of all of them. Please do post if you discover additional features.

[sb1966]

Dear Smith
Thanks for this very useful post. I think there should be a page in the Command Manual replicating your post.

Regards.