To be fair, when writing scripts it's easy to fall foul of differences between GNU and BSD tools, or using an external tool that isn't available by default on s

To be fair, when writing scripts it's easy to fall foul of differences between GNU and BSD tools, or using an external tool that isn't available by default on some systems. Pure bash solutions avoid these problems, and can be just as simple as (or simpler than) an alternative that use external tools.