Is there a Subversion command to reset the working copy?

You can recursively revert like this:

svn revert --recursive .

There is no way (without writing a creative script) to remove things that aren't under source control. I think the closest you could do is to iterate over all of the files, use then grep the result of svn list, and if the grep fails, then delete it.

EDIT: The solution for the creative script is here: Automatically remove Subversion unversioned files

So you could create a script that combines a revert with whichever answer in the linked question suits you best.

To revert tracked files

svn revert . -R

To clean untracked files

svn status | rm -rf $(awk '/^?/{$1 = ""; print $0}')

The -rf may/should look scary at first, but once understood it will not be for these reasons:

1. Only wholly-untracked directories will match the pattern passed to rm
2. The -rf is required, else these directories will not be removed

To revert then clean (the OP question)

svn revert . -R && svn status | rm -rf $(awk '/^?/{$1 = ""; print $0}')

For consistent ease of use

Add permanent alias to your .bash_aliases

alias svn.HardReset='read -p "destroy all local changes?[y/N]" && [[ $REPLY =~ ^[yY] ]] && svn revert . -R && rm -rf $(awk -f <(echo "/^?/{print \$2}") <(svn status) ;)'

Delete everything inside your local copy using:

rm -r your_local_svn_dir_path/*

And the revert everything recursively using the below command.

svn revert -R your_local_svn_dir_path

This is way faster than deleting the entire directory and then taking a fresh checkout, because the files are being restored from you local SVN meta data. It doesn't even need a network connection.