Can updating the hosts file in Windows via batch file cause harm?

Question

I have this script that I have saved as a .bat file. Can it hurt a computer?

echo # >> %Windir%\System32\drivers\etc\hosts
echo 0.0.0.0    www.facebook.com >> %Windir%\System32\drivers\etc\hosts

I was just wondering if this can have any side effects on the computer at all like a corruption of something? I don't think it is possible. All it does is make Facebook show a DNS error by changing the hosts file.

Solution

Normally I've seen people use localhost instead of 0.0.0.0. I don't know the reason for this; but it shouldn't be a big deal.

Other than that; this script is completely okay. Note that you will not be able to use Facebook after running this script but I think that's what you're trying to accomplish.

Comments

[0xC0000022L]

If you want to get rid of Facebook there are better alternatives (addins/extensions) for the various browsers. This will work, but facebook.com has so many subdomains it's almost pointless. Also a proxy (Privoxy etc) can filter web sites and will therefore remove any links to facebook, for example. Anyway, without fuzzy matching this makes not much sense and the hosts file doesn't allow for that.

[cutrightjm]

This will have to be run as administrator to work, in case you didn't know. Also, they could just use facebook.com, the ip address, facebook.us, etc... I would recommend another method.

[Megaeverything]

Thanks the reason i put the # in there was for that exact reason. some hosts files dont have another line so i put # there to make it start a new line for the actual remapping. becasue that file dosnt count the # as anything. so does the "." make a new line in the file?

[Dennis]

Yes, echo. (no space between echo and .) prints a newline.

[Dennis]

I checked and the # does no harm, but I still think the newline in the cleaner approach.