Change Sublime Text icon in Linux (Ubuntu)

script.sh

#!/usr/bin/env bash
##
## Replace Sublime Text icons in Ubuntu
##

if [ "$(whoami)" != "root" ]; then
    echo "Script must be run as root, e.g."
    echo sudo "$0"
    exit 1
fi

# Check if imagemagick is installed. If not, install.
if ! dpkg -s imagemagick >/dev/null 2>&1; then
    echo "Imagemagick not installed. Installing imagemagick"
    sudo apt-get --force-yes --yes install imagemagick
else
    echo "Imagemagick is already installed."
fi

# The directory this script is running in
THIS_DIR="$(dirname "$(realpath "$0")")"

echo "Creating Sublime Text icon set for Ubuntu"
# Convert icons and move into folders
TEMP_DIR="$THIS_DIR/TEMP"
TEMP_ICONS="$TEMP_DIR/Icon"
# shellcheck disable=SC2174
mkdir -p -m755 "$TEMP_ICONS"

# Convert icons
for SIZE in 256 128 48 32 16; do
    mkdir -p "$TEMP_ICONS/${SIZE}x${SIZE}"
    convert -resize "${SIZE}x${SIZE}" "${THIS_DIR}/st_icon_512.png" "${TEMP_ICONS}/${SIZE}x${SIZE}/sublime-text.png"
done

echo "Updating Sublime Text icons"

# Replace theme icons in all default locations
for dir in /usr/share/icons/*/ ~/.local/share/icons/*/; do
    ICON_DIRECTORY=${dir%*/}
    # Replace all icon sizes
    for SIZE in 256 128 48 32 16; do
        ICON_SIZE_DIRECTORY="${ICON_DIRECTORY}/${SIZE}x${SIZE}/apps/"
        if [ -d "$ICON_SIZE_DIRECTORY" ]; then
            cp -f "${TEMP_ICONS}/${SIZE}x${SIZE}/sublime-text.png" "${ICON_SIZE_DIRECTORY}/sublime-text.png"
        fi
    done
done

# Replace default Sublime Text 2 icons
SUBLIME_ICONS="/opt/sublime_text/Icon/"

# Remove existing icons
rm -rf "$SUBLIME_ICONS"

# Move new icons into place
cp -rp "$TEMP_ICONS" "$SUBLIME_ICONS"

# Remove temporary icon directory
rm -rf "$TEMP_DIR"

echo "Rebuilding icon cache"

# Rebuild icon cache for all icons
sudo find /usr/share/icons -mindepth 1 -maxdepth 1 -type d | while read -r THEME; do
  if [ -f "$THEME/index.theme" ]; then
    sudo gtk-update-icon-cache -f -q "$THEME"
  fi
done

echo "Icon cache rebuilt successfully"

Read more at https://gxanshu.in/blogs/change-sublime-text-icon