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

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

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

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.

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

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.

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