Do You Just "Shutdown" Or "Shut Down" a System? "Sign In" Or "Sign-In"?

There are terminology errors in technical writing that even some experienced technical writers commit from time to time. The words we use when describing how to turn a system on and off, or how to enter and leave a location, are ripe for such inadvertent errors.
Here are the basics:
“Shutdown” is a noun. “Shut down” is a verb.
“Sign-in” is a noun. “Sign in” is a verb.
“Sign-out” is a noun. “Sign out” is a verb.
“Login” is a noun. “Log in” is a verb.
“Logout” is a noun. “Log out” is a verb.
You see the pattern of course…
When written APART, these two-part words are all VERBS. When written together or with a dash, they are NOUNS.
The rule is valid for other similar terms like “signoff vs. sign off” as well.
Here are some examples of incorrect and correct usage:
INCORRECT:
Who shutdown the system last night?
Be sure to call the guard after you logout of the system and signout at the lobby.
We lost all data after that accidental shut down.
Signin your full name, please.
All managers signedoff on this document.
We can’t release this document without the management’s sign off.
CORRECT:
Who shut down the system last night?
Be sure to call the guard after you log out of the system and sign out at the lobby.
We lost all data after that accidental shutdown.
Sign in your full name, please.
All managers signed off on this document.
We can’t release this document without the management’s signoff.