Shell script to convert PNGs into AVIF/WEBP using Squoosh CLI

#!/bin/bash
if ! [ -x "$(command -v npx)" ]; then
    echo "npm isn't installed." >/dev/null >&2
    exit 1
fi

# TODO add other formats ex: webp
avif() {
    # customise parameters as needed
    local avif_options='{"quality": "30", "effort": "4"}'
    npx @squoosh/cli --avif "$avif_options" $1
}

format=$1
if [ -z "$format" ]; then
    echo "Format arg not specified. pass avif or webp as argument to the script." >/dev/null >&2
    exit 1
fi
if [[ "$format" != "avif" ]]; then
    echo "Invalid format specified" >&2
    exit 1
fi

for image in *.png; do
    base_name=${image%%.*}
    test_file="$base_name.avif"
    if [[ ! -f $test_file ]]; then
        avif $image
    else
        echo "$test_file already exists. Skipping..."
    fi
done

Usage

# Run this script file in the directory where you have png files
./squoosh.sh avif