detect when a webpage is updated

There is a website (very simple) which will be updated soon and I'd like to receive an alert at the moment it changes (like a sound, a popup,...)

I guess I should send开发者_开发技巧 request every x minutes and compare the result with what's now but I don't know how to do that.

I don't really care about the language used, I know java, python, php, a bit of c and bash (I'm on linux)...

Thank you

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An easy way to do it would be to combine wget and cmp with a loop in bash. When the files differ you could use sendmail to throw yourself an email.