Global constant value

[antlomb]

Hello everybody, can you suggest which is the best value to define global constant values which can be used in scripts ? 
For example, constants defining logging levels, urls, usernames and passwords, etc.... I would like to have the constants defined in a global and unique repositories, so that I'm able to eventually change them in one unique place and use them everywhere. 
Thanks a lot for help

[Daniel]

Use user library for this or common function

[antlomb]

Thanks