XDG-MIME(1) xdg-mime Manual XDG-MIME(1)

xdg-mime - command line tool for querying information about file type handling and adding descriptions for new file types

xdg-mime query {filetype FILE | default mimetype}

xdg-mime default application mimetype(s)

xdg-mime install [--mode mode] [--novendor] mimetypes-file

xdg-mime uninstall [--mode mode] mimetypes-file

xdg-mime {--help | --manual | --version}

The xdg-mime program can be used to query information about file types and to add descriptions for new file types.

query file

Returns the file type of FILE in the form of a MIME type.

Please note that FILE names starting with a - will be rejected, this can be mitigated:

•Pass absolute paths, i.e. by using realpath as a preprocessor.
•Prefix known relative filepaths with a “./”. For example using sed -E 's|^[^/]|./\0|' as a preprocessor.

The query file option is for use inside a desktop session only. It is not recommended to use xdg-mime query file as root.

query default

Returns the default application that the desktop environment uses for opening files of type mimetype. The default application is identified by its *.desktop file.

The value returned by this command may or may not match the application launched by xdg-open as xdg-open hands over to desktop specific openers most of the time which may implement their own logic.

The query default option is for use inside a desktop session only. It is not recommended to use xdg-mime query default as root.

default

Ask the desktop environment to make application the default application for opening files of type mimetype. An application can be made the default for several file types by specifying multiple mimetypes.

application is the desktop file id of the application and has the form vendor-name.desktop. application must already be installed in the desktop menu before it can be made the default handler. The application's desktop file must list support for all the MIME types that it wishes to be the default handler for.

Requests to make an application a default handler may be subject to system policy or approval by the end-user. xdg-mime query can be used to verify whether an application is the actual default handler for a specific file type.

Security Note: Never set a handler that will blindly execute code or commands from the file being handled. Such behaviour will sooner than later lead to unintended code execution i.e. through a curious user trying to inspect a freshly downloaded file but running it by accident.

Keeping opening and executing separate actions helps with people protecting themselves from malware, the default handler is an opener, not a runner.

The default option is for use inside a desktop session only. It is not recommended to use xdg-mime default as root.

install

Adds the file type descriptions provided in mimetypes-file to the desktop environment. mimetypes-file must be a XML file that follows the freedesktop.org Shared MIME-info Database specification and that has a mime-info element as its document root. For each new file type one or more icons with name type-subtype must be installed with the xdg-icon-resource command in the mimetypes context. For example the filetype application/vnd.oasis.opendocument.text requires an icon named application-vnd.oasis.opendocument.text to be installed (unless the file type recommends another icon name).

uninstall

Removes the file type descriptions provided in mimetypes-file and previously added with xdg-mime install from the desktop environment. mimetypes-file must be a XML file that follows the freedesktop.org Shared MIME-info Database specification and that has a mime-info element as its document root.

--mode mode

mode can be user or system. In user mode the file is (un)installed for the current user only. In system mode the file is (un)installed for all users on the system. Usually only root is allowed to install in system mode.

The default is to use system mode when called by root and to use user mode when called by a non-root user.

--novendor

Normally, xdg-mime checks to ensure that the mimetypes-file to be installed has a proper vendor prefix. This option can be used to disable that check.

A vendor prefix consists of alpha characters ([a-zA-Z]) and is terminated with a dash ("-"). Companies and organizations are encouraged to use a word or phrase, preferably the organizations name, for which they hold a trademark as their vendor prefix. The purpose of the vendor prefix is to prevent name conflicts.

--help

Show command synopsis.

--manual

Show this manual page.

--version

Show the xdg-utils version information.

xdg-mime honours the following environment variables:

XDG_UTILS_DEBUG_LEVEL

Setting this environment variable to a non-zero numerical value makes xdg-mime do more verbose reporting on stderr. Setting a higher value increases the verbosity.

XDG_UTILS_INSTALL_MODE

This environment variable can be used by the user or administrator to override the installation mode. Valid values are user and system.

An exit code of 0 indicates success while a non-zero exit code indicates failure. The following failure codes can be returned:

1

Error in command line syntax.

2

One of the files passed on the command line did not exist.

3

A required tool could not be found.

4

The action failed.

5

No permission to read one of the files passed on the command line.

xdg-icon-resource(1), xdg-desktop-menu(1), Shared MIME database specification[1], MIME applications associations specification[2]

xdg-mime query filetype /tmp/foobar.png

Prints the MIME type of the file /tmp/foobar.png, in this case image/png

xdg-mime query default image/png

Prints the .desktop filename of the application which is registered to open PNG files.

xdg-mime install shinythings-shiny.xml

Adds a file type description for "shiny"-files. "shinythings-" is used as the vendor prefix. The file type description could look as follows.

shinythings-shiny.xml:
<?xml version="1.0"?>
<mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
  <mime-type type="text/x-shiny">
    <comment>Shiny new file type</comment>
    <glob pattern="*.shiny"/>
    <glob pattern="*.shi"/>
  </mime-type>
</mime-info>

An icon for this new file type must also be installed, for example with:

xdg-icon-resource install --context mimetypes --size 64 shiny-file-icon.png text-x-shiny

Kevin Krammer

Author.

Jeremy White

Author.

Copyright © 2006

1.
Shared MIME database specification
2.
MIME applications associations specification
02/06/2024 xdg-utils 1.0