Deep mining of DOS commands

Winstart. BAT

@echo off

IF not EXIST Z:\ABC\CBA ctty NUL

Explain.

IF (not) ... EXIST ... Executes the statement following if the specified file or directory is detected or not detected. Here, we specify the Z:\ABC\CBA this file, in practice, as long as it is changed to another certainly does not exist (or exist) file on the line.

Ctty, this command should not know many people, it means to redirect input to the specified device.

NUL, empty equipment.

If Z:\ABC\CBA is not detected, the input is redirected to the empty device.

Why put it in the Winstart.bat file? Because it has a lot of special places. 1, it is a Windows automatic batch processing file. 2. The command executed by this file will not be exposed in step, http://www.aliyun.com/zixun/aggregation/34134.html "> Safe mode must skip it." 3, this batch of documents attention to the number of people, is often ignored.

You reader, now understand the power of these command combinations. If I put it into your machine, the boot will be in the blue sky after the white clouds into the dead loop, causing the panic illusion. Tapping the keyboard will beep, press the three key to hot start, press CTRL can not jump out, but can do DOS and safe mode, with a single step to execute or generate BOOTLOG.TXT, or use the System Configuration Editor SYSEDIT.EXE can not detect, anti-virus software is also invalid. And these commands are internal commands for DOS, and there is no command that is not found, and therefore versatile. If you don't check the Winstart.bat file (which is its only drawback), you're going to have to check the hardware and reload the Windows.

If you add a little bit of the functionality of these commands, such as implementing a place, or composing a malicious program, can you laugh?