Star Trek "Dress Uniform" Command Dept.      Command uniforms are worn by those who in a position, that will one day lead to the Admiralty, or the comamnd of a starship. Most command officers wear a mustard yellow, Captain Kirk almost always was seen in a "tea green" shirt. Dress uniforms were often used in officer hearings/courtmartial hearings. They were also often seen in diplomatic occassions.
The Original Series was the first series of Star Trek, and as such, is the template for all later versions. While the 2nd-6th movies appeared to not have a seperate dress uniform, the duty uniform seemed to take after the original series' dress uniform.
Uniforms: Star Trek Uniforms: Dress, Command