julia> a = [4,2,3,1]
4-element Int32 Array:
 4
 2
 3
 1
julia>#non-mutating sort
sort(a)
4-element Int32 Array:
 1
 2
 3
 4

julia> a
4-element Int32 Array:
 4
 2
 3
 1

julia>#mutating sort
 sort!(a)
4-element Int32 Array:
 1
 2
 3
 4

julia> a
4-element Int32 Array:
 1
 2
 3
 4