Hacker News Reader

Comment by Wowfunhappy | Hacker News Reader

> However, while writing programs that need to invoke POSIX commands in a portable manner

...probably a stupid question, but something I have earnestly been wondering about... when does this actually happen nowadays? What POSIX systems are you targeting that aren't one of the major ones (Linux, Darwin, or one of the major BSDs)?

I was writing a shell script a few months ago that I wanted to be very durable, and I targeted sh instead of bash just because, well, it seemed like the correct hacker spirit thing to do... but I don't actually know what system in the past decade (or more) wouldn't have bash.

View on HN

I ~recently had to wrestle w/ TeamCity (CICD) whose build agents provide only sh. I needed to invoke a 3rd-party util that required bash. The resulting "bash in dash in docker in docker" worked, but I wasn't thrilled about the convoluted / Frankenstein setup.

> ... but I don't actually know what system in the past decade (or more) wouldn't have bash.

There's some ambiguity about "have bash". If "having" bash means that (some version of) bash has been ported to the system, there are indeed very few. If "having" means that bash (supporting all options that you need) is available to the user, that could be a lot more. As others have noted, the BSDs, Android and many embedded Linux systems don't come with bash pre-installed, MacOS pre-installed bash is stuck at version 3.2 (which doesn't have associative arrays), and the user could be in an environment that does not allow them to install whatever they need.

Alpine docker images only come with dash instead of bash, which _may_ run your sh script, but test thoroughly. Or just install bash.

FWIW, Darwin/macOS is especially guilty of gobsmackingly ancient coreutils that don’t support long option variants.

Is it? I'm with you on gobsmackingly ancient, but it's "doesn't support long options" which I haven't bumped into. I do replace some coreutils, but not all of them.

What's a good example of such a utility?

For example, sed. macOS sed doesn't support long options. Not even --help or --version

(Running an older version of macOS so can't completely exclude this has been updated in a newer version, but I'd be surprised to learn that was true.)

macOS doesn't have GNU coreutils at all. It has the utils from FreeBSD.

The gobsmackingly ancient GNU software it does have is bash, because it's the last version under GPL 2. I've used Mac OS X since 10.1, so I remember when the default shell was tcsh and /bin/sh was not bash.

That's (basically) the case again on the last few macOS releases. Today, zsh is my shell of choice, including on Linux.

the alpine default shell is called "ash", "dash" is the debian/ubuntu default shell

P in POSIX stands for portability. ,/s

Where I can sometimes get burnt is busybox.

I more often get burnt in zsh to bash than that however

> I don't actually know what system in the past decade (or more) wouldn't have bash.

I have written a bit more about it in these comments:

https://news.ycombinator.com/item?id=40681382

https://news.ycombinator.com/item?id=17074163

FreeBSD doesn’t come with bash though.

But it also have drawbacks :)

But being honest - you can install BASH that way:

# pkg install -y bash

Nor does OpenBSD for that matter.

Major ones are enough. Linux and Darwin (that is, macOS and GNU userspace, really) differ sufficiently that you need to pay attention or limit yourself to POSIX. E.g. sed and wc burned me a few times with scripts that need to run on both.

> but I don't actually know what system in the past decade (or more) wouldn't have bash.

I think MacOS still has bash, so that it, technically, doesn’t count, but it doesn’t have a bash from the past decade, and uses zsh by default.

Reply on news.ycombinator.com