Re: [PATCH] Read /etc/environment first to allow changing environment from user profile

[Tobias Geerinckx-Rice]

Hi Danny,

On 27/07/2016 18:31, Danny Milosavljevic wrote:
>> while read line; do export "$line"; done < /etc/environment
>> 
>> I don't know if Guix even cares about non-bash shells, but this 
>> should™ work in all POSIX®-compliant ones[4]. It's also more 
>> readable.
>> 
>> Thoughts? Gotchas?
> 
> Spaces in keys and/or values don't work that way.
> The read itself already has problems with them.

No. Perhaps you're confusing it with ‘read < /etc/environment’.

Also, there are no spaces in keys, and technically, spaces in values
work just fine: it's the quotes that don't get dropped. D'oh! :-P

Yeah, trying to emulate unquoting (and all manner of escaping that it
entails) would be utter madness. Uglier option [2] it is then:

  . /etc/environment
  while read line; export "${line%%=*}"; done < /etc/environment

It's ugly and racy and less straightforward.
But then so was the original, I guess.

> You might try setting IFS="
> " but not sure whether that's standards-compliant.

Setting IFS to a newline doesn't make sense here.

To be honest, I've a personal dislike for IFS, though it is
POSIX-compliant. Saving IFS, setting IFS to ‘=’, running ‘read key
value’, ignoring ‘value’, and restoring IFS would work.

> Also, does csh actually support "export"? The one I have in Solaris 
> doesn't. You need to do "setenv" there.

csh isn't a (POSIX) sh.

Thanks for the bug spotting,

T G-R

[1]: It seems to be standard, but I didn't bother testing.

> On 27/07/2016 18:02, Tobias Geerinckx-Rice wrote:
> [2]: even if it didn't, section 2.6.2 of [3] has got you covered
> [3]:
http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html