Question

Whenever you download an HTML file from the internet (say, in a zip archive), the first time you open the file in OS X you get a warning something like "this file was downloaded from the internet and may do horrible things to your mother, are you sure you want to open it"? Once you click OK, you can open that file again without further harassment.

Is there anyway to quickly mark a group of these files as safe so the warning doesn't show up the first time you open them?

My specific use case is I've downloaded a large number of HTML files that I'm searching through, and then using the "open" command to open. If I try to open five files at once I get five warning dialogs, which is tedious and irritating.

Answer 1

To fully clean the file, you need to remove the two extended attributes that are used to mark it as a quarantined download, and track where it came from:

xattr -d com.apple.quarantine file-to-clean
xattr -d com.apple.metadata:kMDItemWhereFroms file-to-clean

To save typing and/or typos, you may want to wrap this in a simple shell script...

Answer 2

Remove the verified download plugin located in your /Library/Internet Plug-Ins folder.

I use FlashGot + Speed Download in Firefox and haven't had to deal with those warnings.