test.sh

#!/bin/bash

EXECUTABLE_WEBP_CHECK=$(brew ls --versions webp)

if [[ "" == "${EXECUTABLE_WEBP_CHECK}" ]]; then
    echo "Error: 'cwebp' missing. Please install via 'brew install webp'"
    exit 1
fi

processFile() {
    SOURCE="$1"
    FILENAME=$(basename -- "${SOURCE}")

    DIR=$(dirname -- "${SOURCE}")
    FILE="${FILENAME%.*}"

    (
        set -x
        cwebp "${SOURCE}" -o "${DIR}/${FILE}.webp"
    )
}

if [ -p /dev/stdin ]; then
    while IFS= read line; do
        processFile "${line}"
    done
else
    if [ -f "$1" ]; then
        processFile "${1}"
    else
        echo "This script creates webp from the source files"
        echo
        echo "Usage:"
        echo
        echo "Pipe:"
        echo "  find web/images/foo -type f | ../bin/image-generate-webp"
        echo
        echo "Argument:"
        echo "  ../bin/image-generate-webp web/images/foo/bar.jpg"
    fi
fi