Files in CSV (comma-separted values) format contain tabular data, with rows separated by newlines and columns—normally—separated by a comma (
,). Not every newline has to be a row separator.
There are many CSV variants (partly caused by language settings of the generating spreadsheet programs), so the separator might differ (semi-colon is common in CSVs generated by German software, tabs in others) and cell content might not be quoted (
"...")if not necessary (if not containing the separator character nor any newlines).
For normal CSV files (quotes around fields, newlines and separator character in fields), use a proper CSV parser and tell it what quoting rules the file uses—see Is there a robust command line tool for processing csv files?