  Recent surveys of dust continuum emission at sub-mm wavelengths have shown
that filamentary molecular clouds are ubiquitous along the Galactic plane.
These structures are inhomogeneous, with over-densities that are sometimes
associated with infrared emission and active of star formation. To investigate
the connection between filaments and star formation, requires an understanding
of the processes that lead to the fragmentation of filaments and a
determination of the physical properties of the over-densities (clumps). In
this paper, we present a multi-wavelength study of five filamentary molecular
clouds, containing several clumps in different evolutionary stages of star
formation. We analyse the fragmentation of the filaments and derive the
physical properties of their clumps. We find that the clumps in all filaments
have a characteristic spacing consistent with the prediction of the `sausage'
instability theory, regardless of the complex morphology of the filaments or
their evolutionary stage. We also find that most clumps have sufficient mass
and density to form high-mass stars, supporting the idea that high-mass stars
and clusters form within filaments.
