Regression coefficients without intercept

Could someone recommend a link or help me out here: where can I find the formula for the regression without an intercept, and how is it deriveed differently than the formula with the intercept? (matrix form)

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It's the same formula you use in regression with an intercept: $\hat{\beta}=\left(X^TX\right)^{-1}X^Ty$. Just make sure there isn't a column of ones for the intercept. It's the same derivation as the formula with an intercept.