SecureCRT作为著名的SSH客户端，经常用于登陆远程服务器。在上面编辑文本，特别是用vi打开两个文本，并且需要切换时，很容易出现卡死的现象，不能接受任何的键盘输入。很是郁闷。以前每次遇到这个问题，我只有关掉那个session重新打开一个。这次又遇上，是在不能忍，试着解决一下。

仔细观察会发现，在vi下切换文本“ctrl+w+w”时，很容易输入成”ctrl+s”。随便拿一个session试试就发现，果然是ctrl+s在作怪。只要输入这个，就会卡死。搜索了一下，发现果然是有原因的:

CTRL-S and CTRL-Q are called flow-control characters. They represent an antiquated way of stopping and restarting the flow of output from one device to another (e.g., from the computer to your terminal) that was useful when the speed of such output was low. They are rather obsolete in these days of high-speed networks. In fact, under the latter conditions, CTRL-S and CTRL-Q are basically a nuisance. The only thing you really need to know about them is that if your screen output becomes “stuck,” then you may have hit CTRL-S by accident. Type CTRL-Q to restart the output; any keys you may have hit in between will then take effect.

解决办法:ctrl+s是一个古老的shell控制键，在输入ctrl+q就可以恢复了