I have a csv file say with 100+ columns and I want to extract only specific 60 columns as a subset(both column name + its value). I know we can use Extract Text processors. Can anyone tell me what regular expression to write? Ex- Lets say from the given snapshot I only want NiFi to Extract 'BMS_sw_micro', 'BMU_Dbc_Dbg_Micro', 'BMU_Dbc_Fia_Micro' columns i.e. Extract only column 'F,L,O'.