Browser caches are interesting places. Firefox, in particular, has many files all with intuitive names like 'FA509DE4d01', and no extensions. Fortunately Unix culture has a method for bringing order to this chaos: 'magic' databases, or files containing bytes found in particular types of files. These allow you to guess a file's type based on its contents. Perl provides 'magic' support in the form of File::MMagic, and the following one-liner uses it to print the guessed types of all files in the current directory. (Update: typo, and removed useless Data::Dumper)

perl -MFile::MMagic -e '$mm=File::MMagic->new; for(glob("*")){$res=$mm
+->checktype_filename($_);print "$_:\t$res\n"}'
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