I have 2 machine setup of rhel7 , one is in terminal mode and the other is in grahical mode , when I run 'who
' command on both the machines why do I get 'tty
' in 2nd column output for the machine in terminal mode and 'pts
' for machine in graphical mode

- 31,554
2 Answers
See here What is the purpose of the pts directory in linux
The pts/0 is telling you which "pseudo terminal" the user was logged in on. In this case it's terminal 0,1,2 etc.
A tty is a native terminal device, the backend is either hardware or kernel emulated.
A pts (pseudo terminal device) is a terminal device which is emulated by an other program (example: xterm, screen, or ssh are such programs).
The :0 means the graphical display number, where display / screen are logical concepts of X windows system (not physical display).
Logins that are done on a real terminal have a real terminal name in column 2 of the who
output.
Logins that are "virtual", (e.g. by ssh or by a GUI) run under a terminal emulation in a so called "Pseudo tty" driver.
pty
is an appreviation for pseudo tty.

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who -H
to see the headings – X Tian Oct 15 '15 at 12:42