the meaning of "exit code" in python

[ElaineKuo]

Hello

I ran a multi_merge code using python and got the following message.
Return exit code 0

Please kindly explain what exit code is and any reference to become familiar with python code for a beginner.

Thanks

[DanPatterson_Retired]

http://stackoverflow.com/questions/285289/exit-codes-in-python
http://answers.yahoo.com/question/index?qid=20101015101810AAdMcbK
It can mean anything that you want it, but a default of 0 generally means that the script ran without error.