Hi all. Today I was messing around with making custom icons in Debian 12 and I was having a heck of a time. I finally figured it out and wanted to share my solution. Below is a .sh script that will automate creating and replacing existing icons (note: your input .svg file must match the name of the existing icon you are trying to replace. Check the folder path below to determine the correct name).

How it works

The script takes a path to an .svg file as an input argument. It then searches the /usr/share/icons/hicolor folder’s subdirectories for .pngs of a matching name, notes their resolutions, and utilizes InkScape to convert the .svg to .pngs and replace the icons.

To utilize, save the script below as an .sh file and provide it an input .svg as follows:

sudo ./icons.sh /home/USERNAME/icon.svg

Script

#!/bin/bash

# Ensure the script is run as root to modify files in /usr/share/icons/hicolor
if [ "$(id -u)" -ne 0 ]; then
    echo "This script must be run with root privileges to access the icons folder."
    exit 1
fi

# Check if Inkscape is installed
if ! command -v inkscape &> /dev/null; then
    echo "Inkscape is not installed. Please install it and try again. (sudo apt install inkscape)"
    exit 1
fi

# Input SVG file filepath
INPUT_SVG="$1"
if [ -z "$INPUT_SVG" ]; then
    echo "Usage: $0 /path/to/input.svg"
    exit 1
fi

# Validate that the input SVG file exists
if [ ! -f "$INPUT_SVG" ]; then
    echo "Input SVG file does not exist."
    exit 1
fi

# Define the base directory where icons are located
BASE_DIR="/usr/share/icons/hicolor"

# Loop through all subdirectories (resolutions) in the /usr/share/icons/hicolor folder
for resolution_dir in "$BASE_DIR"/*x*; do
    # Check if this subdirectory is a valid resolution folder and contains an 'apps' folder
    if [ -d "$resolution_dir/apps" ]; then
        echo "Found apps folder in $resolution_dir"

        # Extract the resolution size
        resolution=$(basename "$resolution_dir")

        # Get the name of the input SVG file
        base_name=$(basename "$INPUT_SVG" .svg)

        # Define the target PNG file path in the current resolution folder
        target_png="$resolution_dir/apps/$base_name.png"

        # Check if a .png file already exists with the same name
        if [ -f "$target_png" ]; then
            echo "Found existing $target_png. Replacing it."
        else
            echo "No existing $target_png found. Creating a new one."
        fi

        # Use Inkscape to convert the SVG to PNG at the correct resolution
        inkscape "$INPUT_SVG" --export-type=png --export-filename="$target_png" --export-width="${resolution%x*}" --export-height="${resolution#*x}"

        # Confirm creation
        if [ -f "$target_png" ]; then
            echo "Successfully created $target_png"
        else
            echo "Failed to create $target_png"
        fi
    fi
done

echo "Icon update process complete!"