Can't open a PDF from Terminal on Mac because it ‘couldn't get a file descriptor referring to the console’
Were you literally typing in the “&lt;“ and “>” characters in that command, or did you mean:

open FILENAME.pdf


Where FILENAME is a place holder variable for potentially any file name?

The redirection characters of &lt; > have special meaning to and get interpreted by the shell and their use as you described might well cause that error message as your command in that case means something akin to ‘make the standard input file descriptor for the open command to be filename.pdf and make its standard output file descriptor to be UNNAMED FILE’

That probably accounts for your error.

F.