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

one of the other tool (besides file) you can use is xdg-mime

eg xdg-mime query filetype <file>

if you have yum,

yum install xdg-utils.noarch

An example comparison of xdg-mime and file on a Subrip(subtitles) file

$ xdg-mime query filetype subtitles.srt
application/x-subrip

$ file --mime-type subtitles.srt
subtitles.srt: text/plain

in the above file only show it as plain text.

Answer 2

file version < 5 : file -i -b /path/to/file
file version >=5 : file --mime-type -b /path/to/file

Answer 3

Try the file command with -i option.

-i option Causes the file command to output mime type strings rather than the more traditional human readable ones. Thus it may say text/plain; charset=us-ascii rather than ASCII text.

Answer 4

file --mime works, but not --mime-type. at least for my RHEL 5.

Answer 5

For detecting MIME-types, use the aptly named "mimetype" command.

It has a number of options for formatting the output, it even has an option for backward compatibility to "file".

But most of all, it accepts input not only as file, but also via stdin/pipe, so you can avoid temporary files when processing streams.