Jwt decode

decode_jwt() {
    local jwt="$1"
    local part

    for part in 1 2; do
        local base64="$(echo "$jwt" | cut -d. -f$part | tr '_-' '+/')"
        local len=${#base64}
        local padlen=$((len % 4))

        if [ $padlen -eq 2 ]; then base64="$base64=="
        elif [ $padlen -eq 3 ]; then base64="$base64="
        fi

        echo "$base64" | base64 --decode | jq .
    done
}

decode_jwt "eyJhbGciOiJ...youJTWhere"