Parmanoir

I had trouble trouble with building the query to find files by extension, so here goes :

	id query = [[NSMetadataQuery alloc] init];

	// Search for .jscocoa files
	id predicate = [NSPredicate predicateWithFormat:@"(kMDItemFSName like[c] %@)", @"*.jscocoa"];
	[query setPredicate:predicate];

	// Restrict search to user's home directory
	[query setSearchScopes:[NSArray arrayWithObject:NSHomeDirectory()]];
	// And go !
	[query startQuery];

When you do a Spotlight search and save it as a smart folder, Finder saves it as a property list. You can then drag it to your favorite text editor and copy the query, and use it with mdfind in Terminal. BUT NSPredicate's syntax is different, you need to tweak it :

• Creating a Predicate Format String From a Spotlight Search in Finder
• Query Expression Syntax