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InitialsDiceBearhttps://github.com/dicebear/dicebearhttps://creativecommons.org/publicdomain/zero/1.0/„Initials” (https://github.com/dicebear/dicebear) by „DiceBear”, licensed under „CC0 1.0” (https://creativecommons.org/publicdomain/zero/1.0/)JI
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185
Joined
10 mo. ago

  • In bash, when you redirect the output of a command to /dev/null, like cat /etc/passwd >/dev/null, you are silencing the output.

    There are cases that this is useful, for example when checking if an application is installed:

    node -v >/dev/null && echo "Node.js is installed"

    This line tries to get the version of Node.js, but it silences the output. That's because we don't care about the version. We only care about whether the execution was successful, which implies the existence of Node.js in the system.

  • Take this shape as an example. The "square" in question consists of AC, BD, the outer AB, and the inner CD.

    Point (5) means that, since the lines AC and BD are radii of the concentric circles, the arcs AB and CD should have the same inner angle. That's because the angle COD is equal to AOB.

    Since, the inner angle is the same, then the outer AOB should, by definition, be 2π - (the inner AOB), because that's how radiants work; a circle is 2π rads.

  • Solution:

    Explanation:

    1. in order for the straight lines to be 90 deg with the circles, they must be radii of circles with same central point
    2. the length of an arc is defined as c = r θ (where r is the radius, and θ is the angle)
    3. we define the inner circle with radius r₁ and its arc L₁ = r₁ θ₁
    4. we define the outer circle with radius r₂ and its arc L₂ = r₂ θ₂
    5. Because of (1), θ₁ + θ₂ = 2π
    6. To create the shape, L₁ = L₂ = r₂ - r₁

    If you start replacing and solving, you will get a 2nd grade quadratic, which has a positive and a negative solution. The positive solution is that magic number.

  • Sure, those could theoretically be used for backdoor access to your computer.

    However, they are trivial to spot on most routers. If you see another device on the ethernet port that your computer connects to, then something weird is going on.

    Another important consideration is the fact that those technologies are meant for ethernet, while most people use laptops with wifi.