Ah, you fell into a trap already! Using foo/* like that is generally "weird", since you let the shell expand. It will, for example, miss files that start with a dot ("."). But not necessarily, it depends on what the shell does!
As for the "trailing /" syntax, I know what you mean, but once you've internalized it, it's easy.
Without trailing slash: Copy the directory (and its contents). With trailing slash: Copy what's in the directory. This makes sense, because with the / you say you want to go "into the directory" and copy then.
And the latter includes files starting with . and all of that, you don't have to worry about it, or about what the shell would do, it's all the directory contents.
So what you want for your example is:
rsync -a foo/ bar
rsync -r foo/* bar would do the same (wrong) thing as cp -r foo/* bar, for the same reasons, the syntax is the same in that regard.
> Without trailing slash: Copy the directory (and its contents). With trailing slash: Copy what's in the directory. This makes sense, because with the / you say you want to go "into the directory" and copy then.
Semi-related: with other stuff symlinks act the same way, for example "ls foo" will show you the symlink (even if it's to a directory), "ls foo/" will traverse the symlink (and show you what's inside the directory).
Note that a trailing slash means to copy the contents when using rsync, but not when using cp (which will copy the directory even if there is a trailing slash). For cp, the correct way to copy only the contents is to use `cp -r foo/. bar`. (This also works with rsync.)
Ah, you fell into a trap already! Using foo/* like that is generally "weird", since you let the shell expand. It will, for example, miss files that start with a dot ("."). But not necessarily, it depends on what the shell does!
As for the "trailing /" syntax, I know what you mean, but once you've internalized it, it's easy.
Without trailing slash: Copy the directory (and its contents). With trailing slash: Copy what's in the directory. This makes sense, because with the / you say you want to go "into the directory" and copy then.
And the latter includes files starting with . and all of that, you don't have to worry about it, or about what the shell would do, it's all the directory contents.
So what you want for your example is:
rsync -r foo/* bar would do the same (wrong) thing as cp -r foo/* bar, for the same reasons, the syntax is the same in that regard.