Now I found:
1 When I run a single script from rational robot for purify test, it works.
2 But when I run a shell script which includes several single scripts, it always can not work well. Maybe at the beginning, it can work well for the first 2 or 3 scripts, then nothing more will be done. The software I tested is not responding, Rational Robot is not responding.

Is there anyone has any experience can share with me? Thanks a lot

Janet