x = cumsum(c(0, runif(100, -1, +1)))
y = cumsum(c(0, runif(100, -1, +1)))
fit = lm(y ~ x)
> names(summary(fit))
[1] "call" "terms"
[3] "residuals" "coefficients"
[5] "aliased" "sigma"
[7] "df" "r.squared"
[9] "adj.r.squared" "fstatistic"
[11] "cov.unscaled"
summary(fit)$r.squared