1. "What keyboard key can I press to create a linefeed character on a Mac?"
2. "I was having some issues with 4D text fields that were getting pasted in HTML code from TextMate which was supposed to be putting in linefeeds."
- Many text editors do not convert existing documents when you change the end-of-line prefs setting. Your setting might apply only to future new files.
- You can verify what is being used with a hex editor such as HexFiend.
- Some older Mac programs still default to Carriage Return for end-of-line rather than the Unix convention of linefeed.
- Some cross-platform development tools try to help by defaulting to the convention used on the computer at runtime. But this can cause confusion as it changes the behavior of your app depending on which computer a user uses. Usually you should hard-code a specific consistent end-of-line. Java and REALbasic switch defaults, and as I recall 4D does too at least in some circumstances.