# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/.*CSF-([^._]*).*/\1/gm;t' <<< "PG.BiologicalProcess
PG.MolecularFunction
20210427_EXPL2_Evo1_CML_DIA44min_CSF-01-R_49.raw.PG.MS1Quantity
20210427_EXPL2_Evo1_CML_DIA44min_CSF-02-R_50.raw.PG.MS1Quantity
20210608_EXPL2_Evo3_CML_DIA44m_60k15k_CSF-01-30R_109.raw.PG.MS1Quantity
20210608_EXPL2_Evo3_CML_DIA44m_60k15k_CSF-01-Sr.raw.PG.MS1Quantity"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html