经常从网上复制的代码都有很多空行，一行行删除太费事，现在我找到了一个方法，按下面的步骤即可一次性把所有的空行删除
1. Click Ctrl+H (quick replace)
2. Tick "Use Regular Expressions"
3. In Find specify "^$\n"
4. In Replace box delete everything.
5. Click "Replace All"
All Blank lines will be deleted.
^ Means Beginning of line
$ Means End of line