The second method also works if otherFolder
already exists. Other than that, there is no difference (assuming that /Users/me/someFolder
is an existing folder). In more detail:
cp -a /Users/me/someFolder /Users/me/otherFolder
If someFolder
is a folder (i.e. a directory — and not a symbolic link to a directory) and otherFolder
already exists (and is a directory or a symbolic link to one), this copies /Users/me/someFolder/some/file
to /Users/me/otherFolder/someFolder/some/file
. If someFolder
is a directory but otherFolder
doesn't exist, this copies /Users/me/someFolder/some/file
to /Users/me/otherFolder/some/file
.
If someFolder
exists but is not a directory (it's a regular file, a symbolic link, etc.), it is copied to either /Users/me/otherFolder/someFolder
if otherFolder
is an existing directory or a symbolic link to one, or to /Users/me/someFolder
otherwise (regular file, other special file, or non-existent).
cp -a /Users/me/someFolder/. /Users/me/otherFolder
If someFolder
is a directory or a symbolic link to one, this always copies /Users/me/someFolder/some/file
to /Users/me/otherFolder/some/file
, regardless of whether otherFolder
existed or not. (Except if otherFolder
is an existing file that isn't a symbolic link or a file, in which case the command will fail.)
In all cases, if the thing to copy is a directory, all of its contents are copied recursively, preserving permissions and modification times. (Access times are also preserved, but they're updated in the source.) That comes from the -a
option.
An equivalent command is
rsync -a /Users/me/someFolder/ /Users/me/otherFolder
Note the trailing /
on the source so that /Users/me/someFolder/some/file
is copied to /Users/me/otherFolder/some/file
. If the source was /Users/me/someFolder
, it would be copied to /Users/me/otherFolder/someFolder
.
rsync
is equivalent to cp -R
in simple cases, but it's cleverer about not copying files that are already present in the destination folder, so it's good for resuming an interrupted copy or for doing incremental backups. Rsync also has a lot of options to do things like select which files to copy.