How can I set an environment variable only for the duration of the script?

On Linux (Ubuntu 11.04 (Natty Narwhal)) in Bash, is it possible to temporarily set an environment variable that will 开发者_如何学运维only be different from the normal variable for the duration of the script?

For example, in a shell script, making an application that saves to HOME portable by temporarily setting HOME to a folder in the present working directory, and then launching the application.

VAR1=value1 VAR2=value2 myScript args ...

env VAR=value myScript args ...

Just put

export HOME=/blah/whatever

at the point in the script where you want the change to happen. Since each process has its own set of environment variables, this definition will automatically cease to have any significance when the script terminates (and with it the instance of bash that has a changed environment).