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Re: "here strings" and tmpfiles
From: |
Chet Ramey |
Subject: |
Re: "here strings" and tmpfiles |
Date: |
Fri, 22 Mar 2019 10:21:12 -0400 |
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On 3/20/19 7:36 AM, Daniel Kahn Gillmor wrote:
> On Tue 2019-03-19 09:31:55 -0400, Greg Wooledge wrote:
>> There are scripts that *rely* on the seekability of the temporary files
>> created by here-documents and here-strings. "Improving" the "situation"
>> would break backward compatibility.
>
> i hope you noticed that of my suggested improvements, only one of them
> (a) breaks seekability. Do you have a preference among the other
> proposals? I'm partial to memfd_create(2) on platforms that support it,
> though i'm not sure how to turn that file descriptor into O_RDONLY
> before the exec.
I can't see one by looking at the man page on the web, but I don't have
ready access to a system that implements memfd_create.
>> There is simply NO valid reason to write <<<"$secret" in a script, and
>> thus there is no need to "improve" anything other than the scripts
>> that are doing that. Use a pipe instead.
>
> Not all tools take their secret inputs on stdin. indeed, some are
> explicitly designed to accept special values on other file descriptors.
>
> How do you replicate 3<<<"$secret" with a pipeline?
This is the kind of thing process substitution is good for.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU chet@case.edu http://tiswww.cwru.edu/~chet/
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Re: "here strings" and tmpfiles, Daniel Kahn Gillmor, 2019/03/19
Re: "here strings" and tmpfiles, Robert Elz, 2019/03/19
Re: "here strings" and tmpfiles, Chet Ramey, 2019/03/22
Re: "here strings" and tmpfiles, Chet Ramey, 2019/03/22