Typically, each email address is placed on a new line. For example:

⚠️ Always double-check permission. Uploading purchased or scraped email lists violates the terms of service of every reputable email marketing platform and can get your account banned.

# Linux/macOS: replace newlines with commas and add a header echo "email" > emaillist.csv cat emaillist.txt | paste -s -d ',' >> emaillist.csv

While they share the same file extension ( .txt ), the context is worlds apart.