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Re: What are desired semantics for /etc/shells?



I don't really get the point here:

> Few people would probably *change* /usr/bin/screen to /bin/screen.
Yes, because screen is not a shell. Screen is terminal multiplexer
which just uses a shell. And as such wrappers go, they're not essential
to the OS, but mere a nice to have user command. 

And now taking a look what /bin is all about:

Quoting FHS 3.0:
3.4. /bin : Essential user command binaries (for use by all users)
3.4.1. Purpose
/bin contains commands that may be used by both the system
administrator and by users, but which are required when no other
filesystems are mounted (e.g. in single user mode). It may also contain
commands which are used indirectly by scripts.

(further down there /bin/sh is even listed as a mandatory asset)

And quoting FHS 3.0 further:
4.4. /usr/bin : Most user commands
4.4.1. Purpose
This is the primary directory of executable commands on the system.

Be aware on that topic that FHS 3.0 does not require /usr to be on the
same partition as the root FS, not even being a local FS of sorts nor
being exclusive for the current machine. Shared network storage is a
valid option. On the other hand it is mandatory for /bin and /sbin they
be available when no other FS can be mounted (i. e. no uplink, damaged
/etc/fstab ...), thus they have to be on the root partition, hence the
condition there has to be at least one shell physically available there
for rescuing purposes.

Now one could argue that everything that is not explicitely a mandatory
asset should go to /usr/bin, and I tend to agree to that, but talking
about shells in particular (and not wrappers) I'd say they're quite
essential to a OS, so there's a valid reason for them to be in /bin. 

But then, I'm known to be a little bit of a bean counter considering
those issues, and thus maybe not the best of advisers here. So take my
comment for what you consider it worth. 

BR
Jo

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