Do you have a favorite unix command?

G'day, for myself it would have to be the one that lets you copy one or more files to another location.


cp [OPTION]... --target-directory=DIRECTORY SOURCE...

I use this to backup a full domain.

I get scared when I use the one below though,
on a unixcodes.txt file it reads


************************************************** ****
rm -f *.* make dam sure you know where you are in!!!!
************************************************** ****

I'm just interested in learning more about unix and hence the question above