Crash course in linear algebra:
Once you understand the concept of dimension of a vector space, and in particular know what a basis is, the next concept is that of a linear transformation, and then the fundamental problem in linear algebra is to classify all linear transformations of a finite dimensional space to itself. The basic model example is the transformation defined by multiplication by X, on the quotient space k[X]/(f) where f = a0+a1X+...+an-1X^(n-1) + X^n is a monic polynomial of degree n. This space has natural basis 1,X,X^2,...,X^(n-1), and in this basis the given map permutes the basis vectors cyclically (i.e. 1 is sent to X, X is sent to X^2,...) until the last one X^(n-1), which is sent to X^n, which in the quotient space equals the following linear combination of the basis vectors: -a0 - a1X -a2X^2-...-an-1X^(n-1). The fundamental theorem says that every linear transformation of a finite dimensional space is a product of these models. I.e. this is essentially the most general linear transformation.
A refinement says that we can reduce to the case where the polynomial f is a power of an irreducible polynomial. Hence over an algebraically closed field like the complex numbers, we can assume the polynomial is (X-c)^n, where c is a constant. In this case, it is more natural to take as basis the set 1, (X-c),...,(X-c)^(n-1), i.e. powers of (X-c) instead of powers of X. In this basis the map sends each vector (except the last) to the next basis vector plus c times itself, and sends the last vector just to c times itself. In this basis the map is said to be in "Jordan form".
The simplest case is when the power of (X-c) is one, and the map is a product of copies of the map multiplication by X on the space k[X]/(X-c), i.e. the space is a product of subspaces on each of which the map is just multiplication by a constant. These are called diagonalizable maps, and there exist some important criteria to recognize some such maps, the simplest of which, over the real numbers, is that the matrix for the map is symmetric about the main diagonal. These theorems are called "spectral theorems".
I would also benefit from some clarification by micromass of his statement that artin barely touches on linear algebra, since he devotes chapters 1,3,4,7 to elementary linear algebra, then combines it with group theory in chapters 8 and 9, (representations of linear groups), and finally in chapter 12, applies module theory to deduce the jordan normal form. So in a sense he gives a complete treatment of all the linear algebra I outlined above, and even uses linear algebra to motivate and illustrate group theory.
I would guess that the message is that Artin's treatment is an advanced one and not recommended for an introduction. It was apparently intended as one for MIT students however and does cover pretty much everything, if somewhat efficiently.