coreutils: The who command

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1 The ‘who’ Command
1 =================
1 
1 The first program is the ‘who’ command.  By itself, it generates a list
1 of the users who are currently logged in.  Although I’m writing this on
1 a single-user system, we’ll pretend that several people are logged in:
1 
1      $ who
1      ⊣ arnold   console Jan 22 19:57
1      ⊣ miriam   ttyp0   Jan 23 14:19(:0.0)
1      ⊣ bill     ttyp1   Jan 21 09:32(:0.0)
1      ⊣ arnold   ttyp2   Jan 23 20:48(:0.0)
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1    Here, the ‘$’ is the usual shell prompt, at which I typed ‘who’.
1 There are three people logged in, and I am logged in twice.  On
1 traditional Unix systems, user names are never more than eight
1 characters long.  This little bit of trivia will be useful later.  The
1 output of ‘who’ is nice, but the data is not all that exciting.
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