A Smart, mimeapps.list-Aware File Opener for Neomutt

Tired of being locked into a single default program for your email attachments in Neomutt? This tutorial will guide you through creating an intelligent file-open-chooser that dynamically reads your system’s mimeapps.list configuration. With a single keypress, you can select from all associated applications to open any attachment, bringing the flexibility of a file manager like Ranger directly into your email client.

Changelog

1. Prerequisites

Before we begin, ensure your system has the necessary software and configuration in place.

1.1. Required Software

This script relies on a few common command-line utilities.

# Arch Linux Installation
sudo pacman -S neomutt rofi file

# Optional: dmenu as a fallback for rofi
sudo pacman -S dmenu

1.2. Existing Configuration

You should already have:

• A working Neomutt setup (e.g., one configured with mutt-wizard).
• A populated ~/.config/mimeapps.list file with your preferred application associations.

2. The Core Script: file-open-chooser

This script is the heart of our new functionality. It identifies an attachment’s file type, finds all associated programs from your mimeapps.list, and presents them in a selection menu.

Step 1: Create the Script’s Directory and File

To keep your scripts organized, we will create a dedicated folder and the script file within it.

# Create the subdirectory for our project
mkdir -p ~/Scripts/file-open-chooser

# Create the script file itself
touch ~/Scripts/file-open-chooser/file-open-chooser.sh

Now, open the file ~/Scripts/file-open-chooser/file-open-chooser.sh and paste the entire content below into it.

#!/bin/bash
set -euo pipefail

# Create a temporary file to hold the attachment content piped from Neomutt
tempfile=$(mktemp)
cat > "$tempfile"

# Determine the MIME type of the temporary file
mimetype=$(file --mime-type -b "$tempfile")

# --- Function to extract available programs from mimeapps.list ---
get_programs_for_mime() {
    local mime="$1"
    
    # Read from both [Default Applications] and [Added Associations] sections
    for section in "Default Applications" "Added Associations"; do
        if grep -q "^\[$section\]" ~/.config/mimeapps.list 2>/dev/null; then
            # Use awk to find and print programs for the given MIME type
            apps=$(awk -v section="$section" -v mime="$mime" '
                /^\[.*\]/ { current_section = $0; gsub(/[\[\]]/, "", current_section) }
                current_section == section && $0 ~ "^" mime "=" {
                    sub("^" mime "=", "")
                    gsub(/;/, "\n")
                    print
                }' ~/.config/mimeapps.list)
            
            if [ -n "$apps" ]; then
                echo "$apps"
            fi
        fi
    done
    
    # Always include a "Default" option to use the system's xdg-open
    echo "Default"
}

# --- Function to convert a .desktop file name to a human-readable application name ---
desktop_to_name() {
    local desktop="$1"
    local desktop_file=""
    
    # Search for the .desktop file in standard system locations
    for dir in ~/.local/share/applications /usr/share/applications /usr/local/share/applications; do
        if [ -f "$dir/$desktop" ]; then
            desktop_file="$dir/$desktop"
            break
        fi
    done
    
    if [ -n "$desktop_file" ]; then
        # Extract the 'Name=' field from the .desktop file
        name=$(grep "^Name=" "$desktop_file" | head -1 | cut -d'=' -f2-)
        echo "${name:-$desktop}" # Fallback to the filename if Name is not found
    else
        echo "$desktop"
    fi
}

# --- Main Logic ---

# Collect a unique, sorted list of programs
programs=$(get_programs_for_mime "$mimetype" | sort -u)
display_programs=""

# Build the display list with readable names
while IFS= read -r program; do
    if [ "$program" = "Default" ]; then
        display_programs="$display_programs$program\n"
    else
        readable_name=$(desktop_to_name "$program")
        display_programs="$display_programs$readable_name ($program)\n"
    fi
done <<< "$programs"

# Show the selection menu using rofi, dmenu, or a terminal prompt as fallback
choice="" # Initialize variable
if command -v rofi >/dev/null; then
    choice=$(echo -e "$display_programs" | rofi -dmenu -p "Open $mimetype with:")
elif command -v dmenu >/dev/null; then
    choice=$(echo -e "$display_programs" | dmenu -p "Open $mimetype with:")
else
    echo "Choose program to open $mimetype file:"
    echo -e "$display_programs" | nl
    read -p "Enter choice number: " num
    choice=$(echo -e "$display_programs" | sed -n "${num}p")
fi

# Exit if the user cancelled the selection (e.g., by pressing Esc in rofi)
if [ -z "$choice" ]; then
    rm -f "$tempfile"
    exit 0
fi

# Execute the chosen program
if [ "$choice" = "Default" ]; then
    setsid xdg-open "$tempfile" >/dev/null 2>&1 &
else
    # Extract the .desktop filename from the selection (e.g., from "Okular (org.kde.okular.desktop)")
    desktop_file=$(echo "$choice" | sed 's/.*(\(.*\))/\1/')
    if [ -n "$desktop_file" ] && [ "$desktop_file" != "$choice" ]; then
        # Use gtk-launch for .desktop files, as it's the proper way to launch them
        setsid gtk-launch "$desktop_file" "$tempfile" >/dev/null 2>&1 &
    else
        # Fallback to xdg-open if something went wrong
        setsid xdg-open "$tempfile" >/dev/null 2>&1 &
    fi
fi

# Clean up the temporary file after a delay to give the program time to open it
(sleep 60; rm -f "$tempfile") &

Step 2: Make the Script Executable

Your shell needs permission to run the script file.

chmod +x ~/Scripts/file-open-chooser/file-open-chooser.sh

3. Neomutt Integration

Now, let’s teach Neomutt our new trick. We will bind the o key (for “open”) in the attachment view to execute our script directly.

Add the following line to your Neomutt configuration file (e.g., ~/.config/mutt/muttrc):

# Add a macro to the attachment menu (key 'o') to pipe the
# attachment to our script by calling it with its full path.
macro attach o "<pipe-entry>bash $HOME/Scripts/file-open-chooser/file-open-chooser.sh<enter>" "Choose program to open attachment"

4. Usage in Neomutt

Your new workflow is simple and efficient:

1. Navigate to an email with an attachment.
2. Press v to open the attachment view.
3. Use the arrow keys to select the desired attachment.
4. Press o (our new macro).
5. A Rofi (or dmenu) window will appear, listing all compatible programs.
6. Select a program, and the file will open.

Example Workflows:

• PDF Attachment → o → Choose between Okular, Zathura, Evince…
• Image Attachment → o → Choose between Viewnior, GIMP, Inkscape…
• Video Attachment → o → Choose between MPV, VLC…

5. Customization

To add a new program to the list for a specific file type, simply edit your ~/.config/mimeapps.list file. The changes are picked up by the script immediately, with no need to restart anything!

Example [Added Associations] section:

[Added Associations]
application/pdf=org.kde.okular.desktop;org.pwmt.zathura.desktop;org.gnome.Evince.desktop;
image/jpeg=viewnior.desktop;gimp.desktop;

Another Useful Keybinding

You can still define a separate shortcut to always use the default system application without seeing the menu.

# Add this to your muttrc. 'O' (Shift+o) will open with the default handler.
macro attach O "<pipe-entry>xdg-open<enter>" "Open with default application"

6. Troubleshooting

If things don’t work as expected, here are some common issues and their solutions.

7. Conclusion

By implementing this file-open-chooser, you’ve significantly enhanced Neomutt’s capabilities. Your setup now:

• ✅ Leverages your existing mimeapps.list configuration without duplication.
• ✅ Works universally with any file type.
• ✅ Provides flexible application choices with a single keypress.
• ✅ Integrates elegantly with modern tools like Rofi.
• ✅ Is robust, with fallbacks for different system configurations.
• ✅ Is easy to set up with a direct, simple configuration.

You now have the same power and flexibility to open files in your email client as you do in your file manager.

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