bind vs pwd

[philw@plan9.research.att.com philw@plan9.research.att.com]

>From:	Philip Guenther <stolaf.edu!guenther>
>Sender: cse.psu.edu!owner-plan9-fans
>Precedence: bulk
>Reply-To: cse.psu.edu!plan9-fans
>
>>Given bind -c /usr/$user/tmp /tmp
>>if I cd to /usr/$user/tmp and then cd .., pwd says that I'm now in /.
>>I expected to be in /usr/$user.  Is that how it's supposed to work,
>>or am I all confused about something?
>
>bind is not like ln -s.  The bind command shown above makes /tmp into
>a union directory, containing the union of the previous contents of /tmp
>(probably nothing in this case), and the contents of /usr/$user/tmp.
>In addition, the -c flag specifies that files created in /tmp should
>*really* be created in /usr/$user/tmp.  This is critical here as /tmp
>is unwritable previous to this.
This is incorrect. The bind command is specified
as MREPL with no options. There is no union directory.
/usr/$user/tmp replaces /tmp.