why can't I copy a directory without using -R ?
 

why can't I copy a directory without using -R ? It shows "cp: omitting directory" .

Hi,

cp is meant (without any options) to only work on the current working directory and _not_ on any subdirectories (with or without files). As stated in the man page, you need to use -R to copy recursively.

This is the way it is implemented.

Hope this helps.

You can.
If you don't agree with the implementation, write your own.

Because in Linux, directories don't actually contain files. They contain a list of "addresses" to files. So just directly copying the directory wouldn't copy the files inside.

The -R option tells cp that when it comes across a directory, it should create a new directory in the destination, and start copying files from the subdirectory.

But personally, I think it's really stupid that cp doesn't recursively copy dirs by default, as if that's not what you always need and expect.