file: doesn't appear to be a documented command, while filetype is [1]
Searching for a few random queries with either "file:pdf" or "filetype:pdf" shows that both return pdfs, but the results that I get are different. Not sure what to make of that or which is better.
Searching for a few random queries with either "file:pdf" or "filetype:pdf" shows that both return pdfs, but the results that I get are different. Not sure what to make of that or which is better.
[1] http://www.googleguide.com/using_advanced_operators.html