shell scripts symbol ": >"

I m a newbie at shell scripting, recent开发者_StackOverflow中文版ly I saw a command ": > file" in the script, I dint understand the meaning, can any tell me what's the command doing?

Thanks, in advance

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: is a no-op. > is a redirection, so the file is overwritten with the output from the no-op command (i.e. the file exists and is empty afterwards).

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It creates and/or empties the file. The : command is a bash built-in that just does nothing.