Occasionally you might — or at least I do, from time to time — come across a file with no clear indication what it is or where it’s supposed to go.
The file tool is helpful a times like that. file attempts to figure out what mystery files are, by skimming through a series of tests and giving the first result that works.
As you can see in the example, my hnb notes file comes out as an XML text file, which is 100 percent correct. I can also ask for a mime type, which you see there.
file tries to match archives too, but also can dig through archives and check the contents. That might be a particularly useful tweak sometimes.
I see in the man pages that file can also look at drive partitions and tell you what the contents are. This might seem an odd chore for file, but remember, everything is a file.
So if you have a mystery partition on a drive and you’re not sure if it’s a leftover Windows installation or someone’s secret data stash, file might be able to give you a hint.
Other than that, and the fact that (according to the man page) the file tool in some form or another dates back November 1973, I can’t think of much else to say. Except maybe … Happy Birthday!