If you have a CSV file and want to replace each comma with a carriage return or new line in Linux, you can do so using the tr command. Below is an illustration of how it can be done.
Open a terminal window, then type the following command.
$ cat mycsvfile.txt | tr ',' 'n' > aaa.txt <enter>
This command is useful to convert a list of email address received in the To, cc, bcc fields of an email.