topic SU loosing $HOME parameter in Operating System - HP-UX

SU loosing $HOME parameter

massimo_38 — Thu, 29 Jul 2004 03:01:22 GMT

Hi!
Does anybody know if is it possible to retain the $HOME variable even after a su (or su -) command?

I mean:

1) I'm using the user "alpha" with home: /home/alpha
2) alpha makes "su beta"
3) I'd like that $HOME is still /home/alpha.

Same thing with $LOGNAME...can I have the same $LOGNAME even after a su or a su - ?

Thanks in advance.

PS Actually I make aplha write a file with his $HOME and Beta read this file overwriting his $HOME with the variabile in the file! ;-)

Re: SU loosing $HOME parameter

Jose Mosquera — Thu, 29 Jul 2004 03:04:50 GMT

Hi,

To keep your current environment use:
#su

To set environment use:
#su -

Rgds.

Re: SU loosing $HOME parameter

Michael Tully — Thu, 29 Jul 2004 03:13:20 GMT

Using:

$ su (will keep the same environment, but not retriev the env of the new user)

$ su - (will pick up env of the new user)

Re: SU loosing $HOME parameter

Borislav Perkov — Thu, 29 Jul 2004 03:14:32 GMT

Hi,

I think that you make mistake typing
su beta
instead
su - beta
Try with last one it will solve your problem.
Regards,
Borislav

Re: SU loosing $HOME parameter

Jose Mosquera — Thu, 29 Jul 2004 03:21:06 GMT

Hi,

Always you can force any environmental variables, i.e:

#whoami
user1
#echo $HOME
/home/user1
#su - user2
#whoami
user2
#echo $HOME
/home/user2
#export HOME=/home/user1
#echo $HOME
/home/user1
#pwd
/home/user2
#cd
#pwd
/home/user2 <-- $HOME assignament works
#export LOGNAME=user1
You can change $LOGNAME, but you never will the new user assignament.
#echo $LOGNAME
user1
#whoami
user2

Rgds.

Re: SU loosing $HOME parameter

Muthukumar_5 — Thu, 29 Jul 2004 03:24:42 GMT

If you want to have that change then use su -

su - will use the profile of a particular user in the But su will try to use the situation as "The previously defined HOME and ENV environment variables are removed"

See su man page. It will give the difference between su with - and su without -

Re: SU loosing $HOME parameter

massimo_38 — Thu, 29 Jul 2004 03:55:50 GMT

Thanks to everybody!

I knew that "SU - user" will get the new environment of the new user....but I want to become the new user while retaining the old environment.

If I make "su - user" I get the new environment and I loose the old correctly.

The solution is to export the variable (export LOGNAME, export HOME etc) but in shell script I don't know who is the firt user when I SU to the second.

I mean:

In the profile of the first user alpha I have:

su - beta

so...I become beta and I forget anything about alpha...so I can't get /home/alpha...whitout a crystal ball ;-)

Anyway, Thanks to everybody

Emanuele

Re: SU loosing $HOME parameter

Muthukumar_5 — Thu, 29 Jul 2004 05:16:35 GMT

If you use su to change login from one user to another user then $HOME settings and environment variables set in the prev. will be lost.

But not the $LOGNAME parameter. It will be there as same as in the first login upto you use su -

--- su man page ---
The previously defined HOME and ENV environment variables are removed. ( on su without - )

I have tested the $LOGNAME parameter.

node1> echo $LOGNAME
user1
node1> su node2
node2> echo $LOGNAME
user1

So only $HOME variable and shell variables which was set at prev. user login.

Re: SU loosing $HOME parameter

Jose Mosquera — Thu, 29 Jul 2004 05:47:37 GMT

Hi again,

Then save the alpha environment user's settings before any change, i.e:

#whoami
alpha
#echo $HOME $LOGNAME
/home/alpha alpha
#env > old.env
#su - beta
#echo $HOME $LOGNAME
/home/beta beta
#OLD_HOME=`grep ^HOME= old.env|awk -F"=" '{ print $2 }'`
#OLD_LOGNAME=`grep ^LOGNAME= old.env|awk -F"=" '{ print $2 }'`
#echo $OLD_HOME $OLD_LOGNAME
/home/alpha alpha
#export HOME=$OLD_HOME
#export LOGNAME=$OLD_LOGNAME
#echo $HOME $LOGNAME
/home/alpha alpha

Rgds.