Scrubbing the environment

Processes you call via exec inherit your environment unless explicitly told not to.

Use 'execle' in C -- you can send it a array of environment variables.

In Perl, do a fork, clean up %ENV, and then exec;
           $NEWENV{TERM} = $ENV{TERM};
           $NEWENV{EDITOR} = $ENV{EDITOR};
           %ENV = %NEWENV;
           exec "/bin/program", "arg1", "arg2", ... ;

Always best to create an empty environment and include necessary values, rather than removing values.