How to use program to set enviroment in the current shell?

[jacklee]

I want to develop a program to set enviroment of current shell. I try to use putenv function, but it can only set enviroment on current process. How can I do ? By the way, can complete this task with Java?

Any suggestion is appreciated.

[Klaus Crusius]

The bad news for you. You cannot change the environment of the curretn process(shell) by calling a child process. That is part of the Unix philosophy, I guess.
The good news. There are some ways around.
1. Source a shell file
( #. shell_script_setting_parameters
2. Set enviroment for a child process.
(# env name=value command)
3. Write your own program simulating env
4. If you want to pass output from a child process and modify environment variables of the parent shell:
from the child process create output on stdout in the form "NAME='value';export NAME".
execute the output "eval $(child_process)"
5. Write output in form of a script to a file and source in file (see. 1.)

Excpecting some points, Klaus

[Kenneth Platz]

Jacklee,

The only thing I can think of doing would be to write a program that does something similar to the following:

#include
#include

void main() {
uid_t uid;
struct passwd *pw;
.
/* Tinker around with your environment here */
.
.
uid = getuid();
pw = getpwuid( pw );
execl( pw->pw_shell, pw->pw_shell );
}

And then exec myprogram. You won't have the SAME shell you started out with, but you'll have a shell (as defined by the /etc/passwd entry) that has all of your new environment variables defined in it.