svn up --set-depth exclude dir2
http://*.com/questions/1439176/svn-can-you-remove-directories-from-a-local-checkout-only-not-from-the-reposit
http://cache.baiducontent.com/c?m=9d78d513d98205f34fede5394f4084204e4380122ba6a1020bde843898732f375321a3e52878564291d27d141cb20c19afe73605615465e0c7df883d86e68f6b328b25307117&p=8765da0dc0934eac58edde2d02149f&newp=9b57c64ad4db1bff57ee947e5a4291231610db2151d4d51e678e&user=baidu&fm=sc&query=svn+update+%CC%F8%B9%FD&qid=90bbde7500024cc5&p1=2