When POMS launches jobs, after it builds the full 'ssh user@hostname "setup_stuff; launch_command"',
it performs python '%' substitution with some values. More exactly, the following strings will
be replaced:

%(dataset)s The dataset for this step of execution -- either the overall dataset for the campaign, the result of partitioning the overall Campaign's input dataset in the first step of a partitioned workflow, or the dataset defined by POMS to be the appropriate child files of the previous steps inputs.

%(version)s The version string from the Campaign or Campaign Stage

%(group)s The experiment/group we are currentlyworking on behalf of.

%(experimenter)s The person who hit the launch button on the submission.