Linux all logged users

How to show current logged in users in Linux

All user names are stored in /etc/passwd file and can be displayed with help of cat command or grep command/egrep command:
cat /etc/passwd
grep ‘^userNameHere’ /etc/passwd
grep ‘^tom’ /etc/passwd
Let us see all examples and usage in details.

How to show current logged in users in Linux

• The current time ( 22:11:17 )
• How long the Linux server has been running (18 days)
• How many users are currently logged on Linux (2 users)
• The system load averages for the past 1, 5, and 15 minutes (1.01, 1.04, 1.05)

The following info displayed for each current logged in user:

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• sweta – Login name
• pts/10 – The tty name
• minitx – The remote host/desktop/laptop name
• 22:11 – Login time
• 5.00s – Idle time
• 0.04s – JCPU (it the time used by all processes attached to the tty. It does not include past background jobs, but does include currently running background jobs.)
• 0.02s – PCPU (it is the time used by the current process, named in the “what” field.)
• vim replicant.py – The command line of their current process

Find out who you are currently logged in as on Linux

Execute the following command:
whoami
Another option is to just type the following id command:
id

Use the whoami and id commands to find out who you are currently logged in as on Linux based system

Linux show who is logged on

Conclusion

This page showed how to find out current logged in users in Linux and what they are doing from the terminal. For more info see man pages using the man command:
man w
man who
man whoami

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UNIX / Linux List Current Logged In Users

H ow do I print the user names of users currently logged in to the current UNIX / Linux host / server from a command prompt?

You need to use any one of the following command line tools to list currently logged in users on Linux or Unix-like systems.

Tutorial details
Difficulty level	Easy
Root privileges	Yes
Requirements	w or who command on Linux and Unix
Est. reading time	5m

The following two file keep login records on Linux and Unix-like systems:

• /var/run/utmp – Keeps and allows us to discover information about who is currently using the system. Please note that there may be more L inux and Unix users currently using the system, because not all programs use utmp logging . In other words, poorly written app, hidden programs, malware, and other bad stuff will not be useful to list logged in users.
• /var/log/wtmp – Keeps records all logins and logouts.

We simply cannot read these files using cat command/grep command/egrep command as file is in binary database format. Hence, we use the following commands to find currently logged in users in Linux and Unix-like systems.

Linux Command To List Current Logged In Users

1. w command – Shows information about the users currently on the machine, and their processes.
2. who command – Display information about users who are currently logged in.
3. users command – See the login names of the users currently on the system, in sorted order, space separated, on a single line. It reads all information from /var/run/utmp file.

How to find currently logged in users in Linux

Open a terminal (or login into remote server using ssh command) and type the following commands.

Using w command to list current logged in users under Unix or Linux

Open the terminal application and then type the w command:
$ w

Fig.01: w command in action.

Understanding w command outputs

From Fig.01 we see the following for each user:

• USER – Linux or Unix login name.
• TTY – The tty name.
• FROM The remote host or IP address.
• @Login – Login time.
• IDEL – Idle time.
• JCPU – The JCPU time is the time used by all processes attached to the tty. However, it does not include past background jobs, but does include currently running background jobs.
• PCPU – The PCPU time is the time used by the current process, named in the “what” field.
• WHAT – The command line of that users current process.

To see info about a user named tom, enter:
$ w tom
Tell w command not print header:
$ w -h
$ w —no-header
We can also ignore current process username by passing the -u or —no-current to the w command:
$ w -u
$ w —no-current
Want to see remote hostname field? Try:
$ w -f
Show IP address instead of hostname for from field:
$ w -i
We can also old style output. In other words old outputs prints blank space for idle times less than one minute:
$ w -o

Display all logged in users using who command

The who command works on all Unix like operating systems such as macOS, *BSD, Linux and so on. The syntax is pretty simple:
# who
Here is what we see:

The who command displays the following information:

• root – The username
• pts/0 – Type of the terminal device. In this example, we see pseudoterminal pts/0 used by root user.
• 2013-03-12 15:10 – User login date and time stamp.
• (10.1.3.177) – The remote IP address from which the user logged into this server.

We can pass the -a option to who command as follows to see time of last system boot, display dead processes, system login processes, active processes spawned by init/systemd, print current runlevel, print last system clock change, show user’s message status, and list users logged in to Linux or Unix box:
# who -a
Here is output from older Linux system (pre Systemd):

Sample outputs from Systemd based Linux sysetem:

Getting help with the whois command

You can pass the following options to the who command (taken from the who command man page):

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users command

Open a terminal or login over the ssh session and enter the following users command:
$ users
Output who is currently logged:

Vieing logged in users with last command

Want to see a listing of last logged in users? Use the last command to lookup binary database called /var/log/wtmp and displays a list of all users logged in (and out) since that file was created. For instance see history for user named ‘vivek’:
$ last vivek

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3 ways to list all currently logged in users in linux

Many a time in multi-user environments like Linux, you want to find all the logged in sessions or list all logged in users. This will allow you to know if there has been any ‘defunct‘ sessions which has hanging around for long. This might even be necessary from a security perspective. It could also help you to figure out if there is any particular user and process that is hogging the system resources.

The list of all logged in users will be a subset of all the users that are in the system. If you like to see the list of all users in a Linux system, then you will need to use different set of commands than the ones mentioned in this post.

w command

The w command is a combination of some of the commonly used Linux commands, such as who, ps and uptime and provides a comprehensive output of the logged in users.

The w command, without any command line options will show you a list of all the users who are currently logged in to system and the information about all the processes that are currently running. By default it should show you the user name, the login time, the CPU resources consumed by each process, the terminal (or tty) and the executing command.

Specifying a particular username to the w command will let you see all the sessions of that particular user and just the processes run by that user. Substitute the username field in the example above with the actual login name of the user.

who command

Another command that you can use is the who command, which is closely related to the w command above. Compared to the w command, the who will print out much more concise information. It usually skips the detailed process information by default and shows you the user name and the tty information.

There are some useful command line options available with the who command…

-b (or –boot) : this will print out the time of the last system boot
-d (or –dead): prints out some information about processes that are dead or defunct
-a (or –all): this enables a bunch of useful options such as -b, -d, -l, -p etc.

This will list all logged in users along with detailed information about each session and terminal.

users command

Sometimes, you just want to know the logins of the users who are currently logged in. The users command will print out just the user or login names with out any of the other information such as login times and process information.

This will list all logged in users. However, if a user has multiple sessions then it will print out the user name for each session. The previously mentioned commands w and who also outputs the user name for each session. It shows looks redundant or repetitive in this case as there is no additional information about the session.

Output Customization

Sometimes, the purpose of listing the currently logged in users is to feed it as input to another script or another process. You might be interested in just the username listed just once and uniquely.

You can use several other Linux utilities to do this, such as cut, sort, awk, tr and uniq. We will use some of them below to demonstrate how it works.

bash$ who | cut -d’ ‘ -f1 | sort | uniq

You can use the above output formatting with the w command as well. This will list all logged in users sorted by username and each will be listed just once. Below is the similar command but this time using the w command.

bash$ w -h | cut -d’ ‘ -f1 | sort | uniq

Some of the other very generic examples using other commands such as users and who are…

bash$ users | tr ‘ ‘ ‘\n’ | sort -u

bash$ who | awk ‘< print $1 >‘ | sort | uniq

Depending on your requirement, you can further play around with the options of the cut utility to show more fields, such as

bash$ who | cut -d’ ‘ -f1,5 | sort | uniq

Another command that is probably worth mentioning here is last. The last command will display a (usually long) list of all users that were logged-in in the past. This list will contain both the users that are currently logged-in and active as well as users who are not currently logged-in. Use the command line argument -n to limit the list.

bash$ last -n 100

The above command will show the last 100 users who have logged into the system.

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6 commands to list the logged in users in Linux

But how will you check the complete list of logged in users either current or all those attempts which have been made to connect your machine by any user and the status of connection

Here are 6 commands which I use to view the users who have logged in recently or are currently logged in to any particular Linux machine

Method 1

Method 2

last: This command searches back through the file /var/log/wtmp (or the file designated by the -f flag) and displays a list of all users logged in (and out) since that file was created. Names of users and tty’s can be given, in which case last will show only those entries matching the arguments.

# last -a
deepak pts/3 Tue Oct 16 18:01 – 18:01 (00:00) 10.10.10.30
root pts/2 Tue Oct 16 17:51 still logged in 10.10.10.30
root pts/1 Tue Oct 16 14:29 – 18:03 (03:34) 10.10.10.30
root pts/3 Tue Oct 16 11:10 – 13:11 (02:00) 10.10.10.30
root pts/1 Mon Oct 15 20:30 – 13:21 (16:51) 10.10.10.30
root pts/3 Mon Oct 15 18:02 – 18:37 (00:34) 10.10.10.30
root pts/1 Mon Oct 15 15:23 – 18:34 (03:11) 10.10.10.30
root pts/1 Mon Oct 15 10:45 – 15:22 (04:36) 10.10.10.30
root pts/2 Fri Oct 12 18:34 – 15:53 (3+21:19) :2.0
root pts/1 Fri Oct 12 18:07 – 19:34 (01:27) 10.10.10.30
root pts/0 Fri Oct 12 17:57 still logged in :0.0
root tty1 Fri Oct 12 17:56 still logged in :0
reboot system boot Fri Oct 12 17:44 – 18:03 (4+00:19) 2.6.32-220.el6.i686

Method 3

Method 4

finger: If no arguments are specified, finger will print an entry for each user currently logged into the system.

Method 5

who: This command shows currently logged in users with time details

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How to see Logged in Users in Linux

Have you ever been curious about who is logged in to your Linux system? You can always list all the users on your Linux system but not all of them would be logged in all the time.

If you are on a multi-user Linux environment like a Linux server, checking logged in users could be useful and fun at the same time.

In this tutorial, I’ll show you various ways you list logged in users in Linux.

4 Commands to see logged users on Linux

Almost all these commands rely on the data stored in the /var or /proc directory. If you know a little about the directory structure in Linux, you know that these two directories contains data about the running processes on your system.

1. Use w command to see logged in users in Linux

Can it get any simpler than this? Just type a single letter command in the terminal and it will show the currently logged users in Linux.

And here is the output for the w command:

Let me explain a few terms in the output of the w command. The same terms would be used in other commands as well.

TTY gives you information about the terminal used to log on. pts means pseudo terminal slave which indicates that the user logged in via SSH connection.

It shows the IP address of the user’s computer, login time. You can also see for how long a user has been idle (slacking at work? :D).

JCPU is the time used by all processes attached to the TTY and PCPU is the time used by the current process running by the user. You can see this current process under WHAT column.

2. Check who is logged in with who command

Who command is another simple one. Just type who and it will show who is logged on to your Linux system currently.

You can also see the login time and the IP address of the logged on user.

3. Just get logged in users with users command

All the commands you saw so far give you a lot of information about the logged in users. If you are working on a script and want to know just the name of the logged in users, parsing the output of those commands would be an additional and somewhat complicated task.

This is where the users command can help you. This command only outputs the logged in users, nothing else.

4. Using finger command to see logged in users

You may need to install finger command first because not all Linux distributions have it installed by default.

It is available in the universe repository of Ubuntu and you can install it with this command:

Once installed, just type finger in terminal:

And you’ll see who is logged in on your Linux system.

Bonus Tip: see who logged on your system since last reboot

What you saw so far was about the currently logged in users. How would you know if a user logged out?

The last command in Linux gives you information about all the users who logged in to the system since last reboot. It will also show the log in and log out time of the logged out users.

Here’s the output of the last command which is self-explanatory I believe.

I hope this quick tutorial helped you in finding the users currently logged on to your Linux system. If you know some other way to do it, please share your trick with us in the comment section.

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