Because I didn't see the edited version when I was writing my original reply and its too late, I want to call out another problem that you graciously overlooked that we can call #2 since it touches neatly on your #1 and #3 items and #2 is already missing. The extra junk you see in your wsl after the awk step is probably because the other big *NIX problem with shell scripts is my `netstat` or `grep` or even `echo` might not be the same as yours. I originally wrote it on a mac, and while I was checking the man page for netstat to see how old it was and how likely netstat output would change, it occurred to me that BSD netstat and linux netstat are probably different, so I jumped over and re-wrote on a linux box. Entirely possible your version is different from mine.
Heck, just checking between Bash, ZSH and Fish on my local machine here and Bash and ZSH's version is from 2003 and provides a single `-n` option and declares POSIX compliance, but explicitly calls out that `sh`'s version doesn't accept the `-n` argument. Fish provides their own implementation that accepts arguments `[nsEe]` from 2023. Every day I consider it a miracle that most of the wider internet and linux/unix world that underlies so much of it works at all, let alone reliably enough to have multiple nines of uptime. "Worse is better" writ large I guess.
I was worried that my toy problem wasn’t complex enough to reveal these issues!
I had an experience recently trying to deploy an agent on a dozen different Linux distros.
I had the lightbulb moment that the only way to run IT in an org using exactly one distro. Ideally one version, two at the most during transitions. Linux is a kernel, not an operating system. There are many Linux operating systems that are only superficially “the same”.
At least here, we can agree. If I ran a business and allowed employees to run Linux (which is reasonable, IMO), the last thing I want is someone's riced-out Gentoo with an unpatched security exploit onto the VPN.
Heck, just checking between Bash, ZSH and Fish on my local machine here and Bash and ZSH's version is from 2003 and provides a single `-n` option and declares POSIX compliance, but explicitly calls out that `sh`'s version doesn't accept the `-n` argument. Fish provides their own implementation that accepts arguments `[nsEe]` from 2023. Every day I consider it a miracle that most of the wider internet and linux/unix world that underlies so much of it works at all, let alone reliably enough to have multiple nines of uptime. "Worse is better" writ large I guess.