There are a series of commands, depending on what and how much information you want on logged in users. The commands are:
who
w
users
finger (if installed)
Ironically, the command to see who is logged into the system is who. You can also see who is logged on using the wcommand.
The command to display the IP address, subnet mask, and default gateway of the system you are currently on varies by operating system. On Windows, you can use the command ipconfig in the Command Prompt. For Linux and macOS, the command is ifconfig or ip addr show in the terminal.
They give different information, for one thing. The 'who' command is only useful for users who are currently logged into the system. It also gives log in information about when they logged in and from where. It won't tell you who they are (other than there log in name). The finger command will give information like a white pages - who the person is, where their office is, telephone number, a plan and project if they have one. It may be used whether or not the user is logged in. It also will tell you if you can communicate with them.
Use the 'who', 'w', or 'users' command to find out who is logged in.
There are many ways to do this, but the fastest and easiest is to use the 'uptime' command, which will tell you in a summary line how many users are logged in.
If an individual has the same username on the systems being check up on, they could use the command "$ ssh host who" at the prompt for who. This would bring up the listings for all the people who have logged on or off within a certain period of time on this particular system.
Typically the 'exit' command gets you out of the current shell environment you are in; if this is the login shell then you will be logged out of the system.
users
System Time
ifconfig -a
Open a terminal (short-cut key combination: Ctrl + Alt + T) and type a lower-case w and press enter. You can also use whoor whoami with differing results.
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