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Our recent analysis of far-infrared (Herschel) observations indicates a close relationship between the ubiquitous filamentary structures and star formation. Numerical simulations plus morphological evidence Herschel maps suggest that stars form through gravitational fragmentation in filaments. As explained below, recent analyses of multi-scale, kinematically-resolved, observations of the B5 region in Perseus appear to show that gravitationally bound cores form from fragmenting filments relatively quickly. L1689B is analogous to B5 in that it offers a relatively simple case of a young pre-stellar core sitting on a single filament, with a velocity gradient along the filament at parsec scales. We propose VLA observations of NH_3 (1, 1) and (2, 2) line emission of L1689B in order to trace the kinematics from the filament to the core, and {\bf in order to examine the star forming and fragmentation processes in the filament at an early stage}.  \subsection{The case of B5 in the Perseus molecular cloud}  B5 in the Perseus molecular cloud was identified as a young pre-stellar core. Herschel observations shows that B5 sits in a filamentary strcutre, which extends for \~ 2 pc. FCRAO (40-arcsec-resolution)  observations of ^{12}CO (1-0) and ^{13}CO (1-0) line emission show that the B5 region has a complicated velocity structure with multiple velocity components along the line of sight. Later with In higher resolution (30-arcsec)  GBT observations of NH_3 (1, 1) and (2, 2) hyperfine lines, the  B5 NH_3 core embedded in the surrounding CO mess  is found seen  to have a sub-sonic velocity disperson, conforming to the theory of star formation in {\it coherent cores}. By combining the GBT and the VLA data of NH_3 hyperfine lines, Jaime et al. find fragmentation within the coherent core. This provides the first direct evidence of star formation through filament fragmentation. (See Fig. ?) Intriguingly, the projected morphology of the fragmented cores in B5 (with sizes of a few thousand AU) aligns well with the parsec-scale filament they sit in, as identified on the Herschel maps. This seems to suggest that the first stages of star forming process within filaments preserve the structure of the {\it mother filaments}. This is bizarre considering the difference in spatial scales between filaments (\~ a few parsec) and the condensations found by Jaime et al. (\~ a few thousand AU). To understand this phonomenon, it requires further analysis of the kinematics from the filament to the core and observations that are sensitive to the wide spatial scale range, of more young pre-stellar cores in filaments other than B5.