Oh god that just reminded me how often people ignore the question asking for posix shell or “/bin/sh” or other specific shell scripting language… and processed to answer the question using bash, zsh, Perl, python, or even the slightly less wrong (because it is kinda weird to be shell scripting without a moderately normal unix environment) of using a bunch of Unix binary programs to do the requested job without actually solving the core problem of the question, because the tools made it easier…

And then to ice the cake you find the question because your question has been marked as a duplicate of the older question where they answered using unix binary tools… and you specifically asked about doing something in “pure shell script” or something similar to that phrase.

Stack overflow is fundamentally a system design that breaks down at scale due to misalignment of incentives that are necessary for it to work well at smaller scales (as can be seen in the successful operation of various smaller Stack Exchange sites for various topics such as Law, Aviation, Physics, etc)