getting SHELL environment

[HelloLinux]

Hi,

I am using /bin/csh as default shell. From the terminal i use the command echo $SHELL and i get /bin/csh as result.
Now from here i run /bin/bash, it changes the shell to bash, now when i ru echo $SHELL, i
still get /bin/csh only, although i changed to /bin/bash.

From where do i get the correct info? where is this chnage in shell gets updated.

I am having a CPP code, where i need to detect the current shell, and then spawn a new similar shell.

Please help...

[Lakshmipathi]

Hi,

I am using /bin/csh as default shell. From the terminal i use the command echo $SHELL and i get /bin/csh as result.
Now from here i run /bin/bash, it changes the shell to bash, now when i ru echo $SHELL, i
still get /bin/csh only, although i changed to /bin/bash.

From where do i get the correct info? where is this chnage in shell gets updated.

I am having a CPP code, where i need to detect the current shell, and then spawn a new similar shell.

Please help...

I believe that's because $SHELL variable is predefined for each user. thus it's constant value.
type
$env
Above command displays list of user specific values.
You can edit this shell vairble or check out/etc/passwd file has each users default shell type.

giis:506:506:giis:/home/giis:/bin/bash

I'm using bash shell

[HelloLinux]

Thanks....

So what if from my code, i want to detect currently running shell, after i changed to say bash from csh from shell by running /bin/bash. Is there any environment variable which captures the same?

[Lakshmipathi]

I don't think we have shell variable to grap this new shell...It's bit tricky
Say your default shell is csh...then when you got into bash shell...now bash is the child process of csh.
I'm not sure,I think we can achieve what u said,by using getpid() and getppid()
and then using this process id to resolve the process name.
First get process id of csh.
Then get all process id which are child of csh.
get process name of all these child process with help obtained pid.
Check if the name matches bash or ksh or something.

May be some one else will come up with simpler soultion.
HTH.

[valan]

A thought, which I have not tested, simply running 'bash' will not invoke it as a login shell, and it might not set $SHELL because of that. Perhaps invoking it as a login shell will do so.

[crakarjax]

I am running into this problem right now. Have you (or anyone else) found a good solution to this?