Here is a quick way to find out properties of different files directly using the Linux Mint / Ubuntu command line.
1. Open Terminal and type :
file nameoffile
It will display what kind of file type is the given file along with a few other properties. This can be useful when there are a lot of files that need to be checked for properties and then store the information for reference.
For checking out other options supported with file command, use the following :
file --help
Cheers.