Do you call "At ease " or "Attention" if your alone?

No stand up go to parade rest and address the NCO

I certainly have.

If I was alone, I would just snap to the appropriate postition and politely greet whoever it was that entered the area. It never went over wrong in any way. If anything, they would want to see what it was I was working on or what kind of progress I was making because it usually an important task I was executing for my unit.

If your alone you don't call anything. If you see a 1sg or sgm walk in the room you just assume the at ease position until he tells you to carry on. Same with an officer. Except you come to attention until he says carry on or at ease. No sense calling it out of there is no one to call it out to

Depends on the circumstance. If you are alone in your barracks room then probably not. He has already been "announced" by the CQ and you didn't hear it. Pretty silly to "announce" to a room that only you occupy that he has entered. If you are the CQ or SDNCO and it is their first arrival of the day then yes, you are to announce their arrival for the day.

I believe it is supposed to go like: Sargeant or Sir! Or the person's rank -as you come to attention or parade rest.

It does feel silly, but I always did kinda depends on the csm personality.

Yes

Ok, I'm confused. Is it Army custom to yell "attention" for an enlisted person? I realize that Command Seargents Major and First Sargents are high ranking NCO's but in the Navy, we don't yell "attention on deck" for E-7's -E-9's. Also, if you were alone who would have called attention in the first place even if you do call it for an enlisted person? In the Navy, the person for whom attention was called is the one who then says "at ease" or "take your seats" or similar. Is it different in the Army? I'm only talking about when someone enters an indoor space too, btw. That's the way I read the question. I know that for formal formations it's different, it's the same for us in the Navy, but indoors is something else entirely. We don't salute indoors like the Army does either come to think of it.

I’m sure you don’t need to call it out since you’re alone unless you’re in basic training. Parade rest or attention/greeting of the day would be appropriate, all depends on your comfort level in my opinion.