Tell me a story about parent and child commands?

Hello fellow kirupians. ^^

I’m sure this’ll sound a little silly. [COLOR=silver](and n00bish)[/COLOR]

But could someone take the time …and tell me:
what the functions of “parent” and “child” codes are? ^^;

I’m currently scripting, and came across it,
and it seems usefull enouth to know about.

Hope to hear from yous,

-Jiru.