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+---
+title: Change default applications on Linux from terminal
+url: change-default-applications-on-linux-from-terminal.html
+date: 2026-01-15T16:13:13+02:00
+type: post
+draft: false
+tags: []
+---
+
+Changing default applications is done with command `xdg-mime`. This is a
+command line tool for querying information about file type handling and adding
+descriptions for new file types. Make sure you have this program installed.
+
+Application will use `.desktop` files to associate applications with specific
+types.
+
+## Location and structure of `.desktop` files
+
+```sh
+ls /usr/share/applications
+ls ~/.local/share/applications
+```
+
+You can add your own `.desktop` files to `~/.local/share/applications`.
+
+An example of `.desktop` file for Brave browser located in
+`~/.local/share/applications/brave.desktop`.
+
+```ini
+[Desktop Entry]
+Exec=/home/m/Applications/brave
+Type=Application
+Categories=Applications
+Name=Brave Browser
+```
+
+## Query current associations
+
+You can query specific types with `xdg-mime`.
+
+```sh
+xdg-mime query default text/plain
+xdg-mime query default text/html
+xdg-mime query default x-scheme-handler/http
+xdg-mime query default x-scheme-handler/https
+xdg-mime query default inode/directory
+```
+
+Or you can look at the files containing this data.
+
+```sh
+less ~/.config/mimeapps.list
+less /usr/share/applications/mimeapps.list
+```
+
+## Set default application
+
+```sh
+# Set Brave as default browser.
+xdg-mime default brave.desktop x-scheme-handler/http
+xdg-mime default brave.desktop x-scheme-handler/https
+
+# Set Thunar as default file explorer.
+xdg-mime default thunar.desktop inode/directory
+
+# Set Mousepad as default txt editor.
+xdg-mime default mousepad.desktop text/plain
+```
+
+## Interfacing with C
+
+This simple example lists all registered types. But you can see where this can
+go. This could be turned into ncurses CLI application that is used for setting
+and changing default applications.
+
+```c
+#include <gio/gio.h>
+
+int main(void) {
+    GList *types = g_content_types_get_registered();
+
+    for (GList *l=types; l!=NULL; l=l->next) {
+        g_print("%s\n", (char *)l->data);
+    }
+
+    g_list_free_full(types, g_free);
+    return 0;
+}
+```
+
+Compile with `clang -o main main.c $(pkg-config --cflags --libs gio-2.0)`.
+
+## Reading material
+
+- https://wiki.archlinux.org/title/XDG_MIME_Applications
+- https://commandmasters.com/commands/xdg-mime-linux/
+- https://noman.sh/en/pages/xdg-mime
+- https://linux.die.net/man/1/xdg-mime
+- https://wiki.archlinux.org/title/XDG_MIME_Applications
+- https://gnome.pages.gitlab.gnome.org/libsoup/gio/
+- https://docs.gtk.org/gio/