Careful, that's not quite accurate!

The single quotes force a non-interpolative context, just like single quotes around a string. By default, here documents act like double quoted strings. His construct is valid.

Similarly, you can only get away without the semicolon in a place where a statement doesn't need a closing semicolon -- at the end of a block or the end of a file. In this case, it would work if the original poster posted his complete program.

My guess is that adding a newline or something after the terminator would fix it. Perhaps his editor doesn't add an EOF? He could also use exit or __END__.