How can I find out a file's MIME type (Content-Type)?

Question

Is there a way to find out the MIME type (or is it called "Content-Type"?) of a file in a Linux bash script?

The reason I need it is because ImageShack appears to need it to upload a file, as for some reason it detects the .png file as an application/octet-stream file.

I’ve checked the file, and it really is a PNG image:

$ cat /1.png 
?PNG
(with a heap load of random characters)

This gives me the error:

$ curl -F "fileupload=@/1.png" http://www.imageshack.us/upload_api.php
<links>
<error id="wrong_file_type">Wrong file type detected for file 1.png:application/octet-stream</error>
</links>

This works, but I need to specify a MIME-TYPE.

$ curl -F "fileupload=@/1.png;type=image/png" http://www.imageshack.us/upload_api.php

Answer 1

Use file. Examples:

> file --mime-type image.png
image.png: image/png

> file -b --mime-type image.png
image/png

> file -i FILE_NAME
image.png: image/png; charset=binary