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0 pointschasil6mo ago0 comments

There is some subtlety that you are missing here.

Outside of coreutils, let's consider bash and ksh88.

The two have differing behavior in several areas (coprocesses, alias handling, final pipeline fork, etc.), but this divergence in behavior happened before POSIX.2 and the standardization of the POSIX shell, which is largely a subset of ksh88.

The gist is that activating a mode for POSIX compliance will generally remove functionality, because the standardization happened a decade after development began, and the standards themselves were excessively conservative in adherence to System V.

I've seen that useful GNU extensions are generally adopted by BSD, but much more slowly by POSIX.

That does not serve UNIX well. Someone should challenge the Austin Group for effective control of UNIX standardization.

0 comments

jchw6mo ago

AFAIK, enabling POSIXLY_CORRECT doesn't get rid of any functionality. It changes some very subtle behaviors, such as the way certain argument parsing edge cases would be handled.

Anyway, I think this is somewhat a non-issue: even if bash doesn't fully comply with POSIX standards by default, it should still be possible to be POSIX compliant by delivering a compliant shell in the right place. Though this does make me wonder if there's anything in POSIX that would require the user's default login shell to be POSIX-compliant, Bourne shell compatible. Probably not, right? After all, macOS had been using bash for ages with no issues complying.

chasilOP6mo ago

Nope nope nope.

You can see this in a script by defining:

  alias p=printf

Then try to use it with bash. If bash is running as #!/bin/sh, then it will work, because bash is forced into POSIX mode.

However, if the script is running as #!/bin/bash, then you will be in the '80s behavior, and it will fail.

Try it.

jchw6mo ago

Bash isn't part of GNU coreutils.

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0 pointschasil6mo ago0 comments

There is some subtlety that you are missing here.

Outside of coreutils, let's consider bash and ksh88.

I've seen that useful GNU extensions are generally adopted by BSD, but much more slowly by POSIX.

That does not serve UNIX well. Someone should challenge the Austin Group for effective control of UNIX standardization.

0 comments

jchw6mo ago

AFAIK, enabling POSIXLY_CORRECT doesn't get rid of any functionality. It changes some very subtle behaviors, such as the way certain argument parsing edge cases would be handled.

chasilOP6mo ago

Nope nope nope.

You can see this in a script by defining:

  alias p=printf

Then try to use it with bash. If bash is running as #!/bin/sh, then it will work, because bash is forced into POSIX mode.

However, if the script is running as #!/bin/bash, then you will be in the '80s behavior, and it will fail.

Try it.

jchw6mo ago

Bash isn't part of GNU coreutils.

1 more reply

j / k navigate · click thread line to collapse