  We present explicit expressions for the correlation functions of interacting
fermions in one dimension which are valid for arbitrary system sizes and
temperatures. The result applies to a number of very different strongly
correlated systems, including mesoscopic quantum wires, quantum Hall edges,
spin chains and quasi-one-dimensional metals. It is for example possible to
calculate Coulomb blockade oscillations from our expression and determine their
dependence on interaction strength and temperature. Numerical simulations show
excellent agreement with the analytical results.
