BASH 4.4 mapfile/readarray/read builtins mis-behaving with pipe [edit] documentation bug

Steven Penny svnpenn@gmail.com
Mon Jul 23 02:15:00 GMT 2018


On Sat, 21 Jul 2018 19:36:38, BloomingAzaleas wrote:
> At this time, I do not have a Linux image available to me.

its not that hard to get:

1. http://virtualbox.org
2. http://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid

> you saw the same behavior on Fedora, then I suggest the behavior
> originates upstream at or close the the GNU source-code level.

the behavior is documented by POSIX. Command grouping example:

    $ bash -c 'q=2; (q=3); echo "$q"'
    2

and reference:

> Execute compound-list in a subshell environment [...] Variable assignments and
> built-in commands that affect the environment shall not remain in effect after
> the list finishes.

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_04_01

pipe example:

    $ bash -c 'q=2; echo 3 | read q; echo "$q"'
    2

and reference:

> Changes made to the subshell environment shall not affect the shell
> environment. [...] Additionally, each command of a multi-command pipeline is
> in a subshell environment

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_12

> For a doc counter-example, the Open Group doc at
> http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html

its funny that you list this page, as thats exactly where i got my references.
thanks.

> Thank you for your response.
>
> Regards,
>
> UN*X Since '85

finally i would say to stop top posting. for someone who is self declared unix
for 30 years, it seems odd that you cant even run fedora, or adhere to defacto
mailing list etiquette. Cheers.


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