Why is this script failing to replace the hosts file?

问题

We want to make a change to hosts file of our mobile PC we are adding to our sites. However the client isn't so well versed with computers, that's why I wanted to create a batch file to do the update for them.

The idea is to -Make a copy of the original with the date it was copied. -Update the hosts file.

Due to dealing with win 10 and 7 we found out sometimes we cant straight update the hosts file without copying it first and then override the original. Therefore the procedure I thought would work is this.

Copy of the original with the date it was copied.
Copy the hosts to desktop.
Update the hosts file on desktop.
override the original hosts file.
message if success or failed.

You can see the program doesn't look so difficult, but I encountered an error due to privileges error. So due to our clients having not enough knowledge, I wanted to try and elevate it though my batch file.

I'v tied searching here and found a post "How can I auto-elevate my batch file, so that it requests from UAC administrator rights if required?". But unfortunately my VBS and batch knowledge isn't that high and I hoped someone might help me decipher it.

The code I'v created:

::the copy to desktop command                                                                         xcopy /s C:\Windows\System32\drivers\etc\hosts %userprofile%\desktop

::the update of hosts file                                                                            
echo www.qpv-view.info xxx.xxx.xxx.xxx >hosts

::the date for the copied hosts file                                                               
@echo off                                                                                              
for /f "delims=" %%a in ('wmic OS Get localdatetime  ^| find "."') do set dt=%%a                       
set YYYY=%dt:~0,4%                                                                                     
set MM=%dt:~4,2%                                                                                       
set DD=%dt:~6,2%                                                                                       set stamp=Oldhosts_%YYYY%%MM%%DD%                                                                     
copy /y C:\Windows\System32\drivers\etc\hosts C:\Windows\System32\drivers\etc\%stamp%                                          

::The override of the updated file                                                                    
move /s/Y %userprofile%\desktop\hosts C:\Windows\System32\drivers\etc

end

When I launch, the copy works fine. However the update part requires elevated privileges. However if I start the script with elevated privileges the copy doesn't occur.

回答1:

Because stamp is not defined, this line will copy the hosts file over itself:

copy /y C:\Windows\System32\drivers\etc\hosts C:\Windows\System32\drivers\etc\%stamp%

Because it is equivalent to:

copy /y C:\Windows\System32\drivers\etc\hosts C:\Windows\System32\drivers\etc\

回答2:

It seems that you cannot copy to %userprofile%\desktop while using elevated privileges!

So I just copied the file to drivers folder and all ran fine.

@echo off
for /f "delims=" %%a in ('wmic OS Get localdatetime  ^| find "."') do set dt=%%a
set YYYY=%dt:~0,4%
set MM=%dt:~4,2%
set DD=%dt:~6,2%
set stamp=Oldhosts_%YYYY%%MM%%DD%

copy /y C:\Windows\System32\drivers\etc\hosts C:\Windows\System32\drivers\etc\%stamp%
copy /y C:\Windows\System32\drivers\etc\hosts C:\Windows\System32\drivers

echo www.qpv-view.info 172.16.10.60 >C:\Windows\System32\drivers\hosts

move /y C:\Windows\System32\drivers\hosts C:\Windows\System32\drivers\etc

pause

来源：https://stackoverflow.com/questions/60198999/why-is-this-script-failing-to-replace-the-hosts-file

标签

javascript

batch-file

hosts