slasr(3) on Linux
The text ae3f892ddbbb, as Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
perform the transformation A := P*A, when SIDE = 'L' or 'l' ( Left-hand side ) A := A*P', when SIDE = 'R' or 'r' ( Right-hand side ) where A is an m by n real matrix and P is an orthogonal matrix,