PLUMED contains a number of simple command line tools. To use one of these tools you issue a command something like:

plumed <toolname> <list of input flags for that tool>

The following is a list of the various standalone tools that PLUMED contains.

driver	driver is a tool that allows one to to use plumed to post-process an existing trajectory.
gentemplate	gentemplate is a tool that you can use to construct template inputs for the variousactions
info	This tool allows you to obtain information about your plumed version
kt	Print out the value of $k_BT$ at a particular temperature
manual	manual is a tool that you can use to construct the manual page for a particular action
simplemd	simplemd allows one to do molecular dynamics on systems of Lennard-Jones atoms.
sum_hills	sum_hills is a tool that allows one to to use plumed to post-process an existing hills/colvar file

For all these tools and to use PLUMED as a plugin in an MD calculation you will need an input file.