Re: G-Expressions manual. change user shell in guix config.scm

[rendaw <7e9wc56emjakcm@s.rendaw.me>]

On 5/4/19 8:29 PM, znavko@disroot.org wrote:
> I just want to change user shell. So i know how to do it. And you have cleared a bit for me what is formed object and what is file, and what is file-append function.
>
> May 4, 2019 11:24 AM, "rendaw" <7e9wc56emjakcm@s.rendaw.me> wrote:
>
>> On 5/4/19 8:19 PM, znavko@disroot.org wrote:
>>
>>> (shell #~#$dash) -- compiles too, but again:
>>>
>>> bob $ su - mom
>>> Password:
>>> /gnu/store/bqmib4vf9mr8dkqx4dqpcqrnb93giwci-dash-0.5.10.2:
>>> /gnu/store/bqmib4vf9mr8dkqx4dqpcqrnb93giwci-dash-0.5.10.2: Is a directory
>>> bob $
>> Could you perhaps provide some details on what you are expecting to
>> happen here?  This error is expected - shell needs a path to an
>> executable, not a directory.  Both `#~#$dash` and `dash` become paths to
>> directories.

(file-append obj "some string") is a convenient alternative to
#~(string-append #$obj "some string").

In the latter "obj" becomes (for example)
"/gnu/store/bqmib4vf9mr8dkqx4dqpcqrnb93giwci-dash-0.5.10.2", and
"(string-append ...)" combines
"/gnu/store/bqmib4vf9mr8dkqx4dqpcqrnb93giwci-dash-0.5.10.2" and
"/bin/dash" to produce
"/gnu/store/bqmib4vf9mr8dkqx4dqpcqrnb93giwci-dash-0.5.10.2/bin/dash"