1.如果出现以下错误：
vtysh: symbol lookup error: /usr/local/lib/libreadline.so.6: undefined symbol: UP
解决方法如下:
1.root@localhost:~ # cd /usr/local/lib
2.root@localhost:/usr/local/lib# ls -la libreadline*
3.root@localhost:/usr/local/lib# mkdir /tmp/libreadline_bk
4.root@localhost:/usr/local/lib# mv libreadline.* /tmp/libreadline_bk/.
5.root@localhost:/usr/local/lib# ldconfig
6.root@localhost:/usr/local/lib#apt-get update
2.
如果出现错误——configure: error: vtysh needs libreadline but was not found and usable on your system
解决：
1)到下载软件readline-6.0.tar.gz
执行：
tar -zxvf readline-6.0.tar.gz
./configure
make
make install
2)