cd and --bind mounts for the home directory

[Christos Zoulas]

On Mar 28,  8:52am, dann at ics.uci.edu (Dan Nicolaescu) wrote:
-- Subject: Re: cd and --bind mounts for the home directory

| christos at zoulas.com (Christos Zoulas) writes:
| 
|   > On Mar 26,  7:58pm, dann at ics.uci.edu (Dan Nicolaescu) wrote:
|   > -- Subject: cd and --bind mounts for the home directory
|   > 
|   > | 
|   > | 
|   > | On my Linux laptop use 2 different users when connected to the
|   > | network, with the home directory mounted via NFS and when
|   > | disconnected.
|   > | 
|   > | So I have a user: me with $HOME = /home/me 
|   > | and a user local_user with $HOME = /home2/local_user
|   > | 
|   > | To minimize differences I would like to have /home/me to point to
|   > | /home2/local_user when disconnected. A symlink does not work in all
|   > | cases, doing a "mount --bind" would be the best solution. 
|   > | 
|   > | All is well, except for the tcsh "cd" builtin that behaves strangely. 
|   > | So if I do: 
|   > | 
|   > | mount --bind /home2/local_user /home/me
|   > | cd /home/me
|   > | But now doing:
|   > | pwd
|   > | prints: /home2/local_user
|   > | 
|   > | The same thing works just fine for "mount --bind" any other directory
|   > | except for the home directory. 
|   > | I have tried this with tcsh-6.14.00 and 6.15.00.
|   > | 
|   > | bash, ksh and zsh behave as expected. 
|   > | 
|   > | Any idea what is wrong here? 
|   > 
|   > Nothing is wrong here; tcsh does not have a built-in pwd. if you want one
|   > alias pwd 'echo $cwd'
| 
| I have that already. 
| Please look at this sequence of commands:
| 
| $ mount --bind /home2/local_user /home/me
| 
| $ cd /home/me
| $ echo $cwd
| /home2/local_user
| ^^^^^^^^^^^^^^^^
| 
| And now the same thing with bash:
| 
| $ bash
| $ cd /home/me
| $ echo $PWD
| /home/me
| ^^^^^^^^^

Something must be wrong with your setup:

[12:54pm] 981#mount -o bind /usr /tmp/tmp
[12:54pm] 982#cd /tmp/tmp
[12:54pm] 983#echo $cwd
/tmp/tmp

run 'tcsh -f' and then repeat the same commands you run with bash.

christos