Comment # 3 on bug 1029961 from Dominique Leuenberger

(In reply to Dr. Werner Fink from comment #1)
> Please stop to enforce to move /bin/bash and/or /bin/csh or /bin/tcsh to
> /usr/bin/ ... I do not agree with this.  It is rather useless to move
> essential user command binaries (for use by all users) from /bin/ to
> /usr/bin/ and link them back to /usr/bin/
> 
> http://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.
> html#binEssentialUserCommandBinaries

fun fact: a symlink of /bin/bash to /usr/bin/bash is even covered by FHS-3.0:

The following commands, or symbolic links to commands, are required in /bin:
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^