Auto wrap mode initially on
With auto wrap mode on, if a long line of text reaches the right-hand edge, it will wrap over on to the next line so you can still see all the text. With auto wrap mode off, the cursor will stay at the right-hand edge of the screen, and all the characters in the line will be printed on top of each other.
Change Settings -> Terminal -> Auto wrap mode initially on
当终端输入超过一行时，如果这个选项没有选上的话，会从这一行的开头处覆盖之前的打印，而选上这个选项之后再重启putty软件(并且软件启动之后不要再调整显示宽度了)，输入超过一行的话会放到一个新行去显示。
参考文章