Galois group command for Magma online calculator?

> P< x >:=PolynomialAlgebra(Rationals());

> f:=x^5+5*x-12;

> G:=GaloisGroup(f);

> print G;

Symmetric group G acting on a set of cardinality 5 Order = 120 = 2^3 * 3 * 5

Although the permutation group on [1..Degree($f$)] is permutationally isomorphic to the Galois group, the bijection with the set of roots of your separable irreducible polynomial $f$ is not determined. For more details see the Magma handbook.