Variable assignment in sh

James B. Byrne byrnejb at harte-lyne.ca
Wed Feb 1 19:59:39 UTC 2017


On Tue, January 31, 2017 14:01, Polytropon wrote:
> On Tue, 31 Jan 2017 12:56:40 -0500, James B. Byrne wrote:
>> How would bash become unavailable on this particular system without
>> someone specifically removing it?
>
> A rare occassion, but possible. Let's say in a worst-case scenario,
> /usr isn't mounted, and you need to stick with what's on /, then
> bash, which per default is /usr/local/bin/bash, isn't available.
> However, bash can be linked statically _and_ copied to a location
> on /, then you won't have that kind of problem.
>
> Portability also could be a problem when you try to run something
> that expects bash on a system where bash isn't installed. Always
> keep in mind that bash is _not_ part of FreeBSD, while sh is.

Yes, I will do that from here on.

>
> I know, those are very special cases, and if your goal is not
> portability and "guaranteed availability", then it won't hit you.
> I just thought it's worth being mentioned.

Thank you.  I have found your explanation of what goes on under the
covers very interesting.  In this case I am dealing with a zfs system
so if /usr is not there then neither is /bin.


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