In a previous review, we have considered the Raman spectroscopy of graphene and graphene oxide to understand the number of lines and line shapes to be used for decomposing the spectra. Here we review some literature about the Raman investigation of carbon nanotubes, focusing especially on the line shapes. Consider please the Fig. , already shown in chemRxiv, reproduced from , and compare the cases of graphite, graphene and single-walled nanotube, SWNT. We have a band, the G band, which is at about the same Raman shift, but the SWNT case is showing two components. This is intriguing, since we know that the G band is originated by the graphite layer. In the single-walled nanotubes, a graphite layer is rolled up to form the tube. Consequently, in the Raman spectra we must have the signature of curvature and related broken symmetry and quantization. The result is band splitting. As shown by literature, the Raman spectra are able of giving information about the nature of the nanotubes (metallic or semiconducting) and if they are single-or multi-walled structures. Moreover, Raman spectra are distinguishing the case when we have nanotubes in bundles. We will focus in particular on the components of the G band and on the existence of Breit-Wigner-Fano line shapes. These lines have been previously considered in a review about molybdenum disulfide MoS2. Raman spectroscopy.