How do I determine if a file is a GIF or webp?

Question

I have a file that's .gif extension but I suspect that it's a lie and it's actually a webp. What's the best way to know what format the file is?

On Linux/macOS, with `file BadBoy.gif` maybe? – Mark Setchell Oct 12 '17 at 18:20 — Mark Setchell, Oct 12 '17 at 18:20

score 2 · Accepted Answer · answered Oct 12 '17 at 19:06

2

By looking into file content and checking its magic number. For webp it's WEBP and for GIF file it is GIF87a/GIF89a.

Here you have list of all magic numbers and where it is located in file: https://en.wikipedia.org/wiki/List_of_file_signatures

answered Oct 12 '17 at 19:06

Marcin Orlowski

I used the command here to get the magic number https://stackoverflow.com/a/2147527/60117 – ajma Oct 12 '17 at 22:38
I could probably mention `file` but for some reason (you know, SO is developers' site ;) I assumed you need to do that from your code yourself. – Marcin Orlowski Oct 12 '17 at 23:06

score 0 · Answer 2 · answered Oct 12 '17 at 18:03

0

You can use TrID, an application that uses file contents to determine file type.

answered Oct 12 '17 at 18:03

JimBoh

2 Answers2