svnadmin load — Read a
            repository dump stream from
            stdin.
Read a repository dump stream from
            stdin, committing new revisions into the repository's
            filesystem.  Send progress feedback to stdout.
This shows the beginning of loading a repository from a backup file (made, of course, with svnadmin dump):
$ svnadmin load /var/svn/restored < repos-backup
<<< Started new txn, based on original revision 1
     * adding path : test ... done.
     * adding path : test/a ... done.
…
        Or if you want to load into a subdirectory:
$ svnadmin load --parent-dir new/subdir/for/project \
                /var/svn/restored < repos-backup
<<< Started new txn, based on original revision 1
     * adding path : test ... done.
     * adding path : test/a ... done.
…
        Newer versions of Subversion have grown more strict
            regarding the format of the values of Subversion's own
            built-in properties.  Of course, properties created with
            older versions of Subversion wouldn't have benefitted from
            that strictness, and as such might be improperly
            formatted.  Dump streams carry property values as-is, so
            using Subversion 1.7 to load dump streams created from
            repositories with ill-formatted property values will, by
            default, trigger a validation error.  There are several
            workaround for this problem.  First, you can manually
            repair the problematic property values in the source
            repository and recreate the dump stream.  Or, you can
            manually tweak the dump stream itself to fix those
            property values.  Finally, if you'd rather not deal with
            the problem right now, use the
            --bypass-prop-validation option
            with svnadmin load.