1. Name

cp [man page] - copy files and directories

2. Synopsis

cp [OPTION]... [-T] SOURCE DEST
cp [OPTION]... SOURCE... DIRECTORY
cp [OPTION]... -t DIRECTORY SOURCE... 

3. Frequently used options

-i, --interactive
       prompt before overwrite
-p     same as --preserve=mode,ownership,timestamps
-R, -r, --recursive
       copy directories recursively
-v, --verbose explain what is being done 

4. Examples

Copy directory dir2 and its content into directory dir1:

cp -r dir2/ dir1/ 

Copy all files from dir2 to dir1:

cp dir2/* dir1/ 

Copy file1 from dir1 to dir2 but prompt before overwrite:

cp -i dir1/file1 dir2/ 

Copy file1 from dir1 to dir2 and preserve mode,ownership and timestamps:

cp -p dir1/file1 dir2/