When I type
who in terminal I get this output:
$USER tty2 2017-01-12 12:50 (:1)
What does this smiley
(:1) mean ?
Sometimes this smiley looks like
(:0.0). What does it mean in this case?
Where is an overview about these different brackets?
As you can find out in the manpage by typing
man who, you can enable column headings with the
$ who -H NAME LINE TIME COMMENT bytecommander tty7 2017-01-12 15:26 (:0) guest-c62iz5 tty8 2017-01-12 15:40 (:1)
I have to agree this is not very helpful though, and the manpage also doesn't contain any explanation of the values.
However, I think I can tell you what these columns mean anyway:
NAMEis the username of each logged in user.
LINEseems to contain the TTY through which the user is logged in (TTY1-6 are terminals, TTY7-12 are used by the X display server to show graphical desktops; you switch between them using Ctrl+Alt+F1 - F12).
TIMEis the date and time when the user logged in to their current session.
COMMENT in our cases shows the content of the
$DISPLAY environment variable (normally
:0) in braces, which is also used by the X display server. Only graphical TTYs should have such a value, this column is empty for me on the terminal TTYs.
info page (
info coreutils 'who invocation')
If given no non-option arguments, ‘who’ prints the following information for each user currently logged on: login name, terminal line, login time, and remote hostname or X display.
(:0) simply means X display number 0 on the localhost.
If there are remote users (for example SSH sessions) as well, you may see something like
$ who steeldriver tty7 2016-12-15 13:57 (:0) steeldriver pts/4 2017-01-12 09:32 (192.168.1.4)