User details in linux

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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11 Ways to Find User Account Info and Login Details in Linux

This article will show you eleven useful ways to find the information about users on a Linux system. Here we’ll describe commands to get a user’s account details, show login details as well as what users are doing on the system.

If you want to add users in Linux, use the useradd utility, and to modify or change any attributes of a already created user account, use the usermod via the command line as explained in the following guides:

We’ll start by looking at commands to find a user’s account information, then proceed to explain commands to view login details.

1. id Command

id is a simple command line utility for displaying a real and effective user and group IDs as follows.

2. groups Command

groups command is used to show all the groups a user belongs to like this.

3. finger Command

finger command is used to search information about a user on Linux. It doesn’t come per-installed on many Linux systems.

To install it on your system, run this command on the terminal.

It shows a user’s real name; home directory; shell; login: name, time; and so much more as below.

4. getent Command

getent is a command line utility for fetching entries from Name Service Switch (NSS) libraries from a specific system database.

To get a user’s account details, use the passwd database and the username as follows.

5. grep Command

grep command is a powerful pattern searching tool available on most if not all Linus systems. You can use it to find information about a specific user from the system accounts file: /etc/passwd as shown below.

6. lslogins Command

lslogins command shows information about known users in the system, the -u flag only displays user accounts.

7. users Command

users command shows the usernames of all users currently logged on the system like so.

8. who Command

who command is used to display users who are logged on the system, including the terminals they are connecting from.

9. w Command

w command shows all users who are logged on the system and what they are doing.

10. last or lastb commands

last/lastb commands displays a list of last logged in users on the system.

To show all the users who were present at a specified time, use the -p option as follows.

11. lastlog Command

lastlog command is used to find the details of a recent login of all users or of a given user as follows.

That’s it! If you know any other command-line trick or command to view user account details do share with us.

You’ll find these related article so useful:

In this article, we’ve explained various ways to find information about users and login details on a Linux system. You can ask any questions or share your thoughts via the feedback form below.

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UNIX / Linux Command To Check Existing Groups and Users

H ow do I check the existing Linux / UNIX users and groups under Linux operating system?

You can easily check the existing users and groups under a Linux or Unix-like systems such as HP-UX, AIX, FreeBSD, Apple macOS/OS X and more using the following commands:

Tutorial details
Difficulty level	Easy
Root privileges	No
Requirements	Linux or Unix terminal
Est. reading time	3 minutes

1. getent command : Fetch details for a particular user or group from a number of important text files called databases on a Linux or Unix-like systems. This is portable and recommended way to get information on users and groups.
2. Directly query /etc/passwd for user names or /etc/group file for group names using the grep command/egrep command, and awk command.

Let us see how to check for existing groups and users on Linux and Unix-like systems using command-line.

Method #1: getent command to lookup username and group name

The syntax is as follows to find out if user named foo exists in system:

The syntax is as follows to find out if group named bar exists in system:

Sample demo of all commands:

Fig.01: getent and friends demo on a Linux or Unix system to find out user and group names

Method #2: Find out if user exists in /etc/passwd file

The /etc/passwd file stores essential information required during login. All you have to do is search this file for user name using the following syntax using grep command grep username /etc/passwd
OR we can use the egrep command too:
egrep -i «^ username » /etc/passwd
# search for multiple users
egrep -i «^ username1|username2 » /etc/passwd
For example, find out if vivek user exists or not, enter:
$ egrep -i «^vivek» /etc/passwd
OR
$ egrep -i «^vivek:» /etc/passwd
Sample outputs:

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A quick shell script code:

Normally, exit status is 0 returned if user accounts (lines) are found and 1 otherwise.

Use awk command to search user name

The syntax is as follows to search user named ‘apache’

Find out if group exists in /etc/group file

The /etc/group is an text file which defines the groups to which users belong under Linux and UNIX operating system. Again, you have to search /etc/group file using following syntax:
$ egrep -i «^ groupname » /etc/group
For, example find out if vivek group exists or not, enter:
$ egrep -i «^vivek» /etc/group
# look for vivek or sudo group in /etc/group
$ egrep -i «^(vivek|sudo)» /etc/group

Say hello to id command

The id command is another option to display user / group information for any USERNAME, or the current user. To find out more about user called, tom, enter:
$ id tom
Sample outputs:

id command exit status is 0 returned if user accounts (lines) are found and 1 otherwise. A sample shell script using id command:

How to list all users under Linux or Unix

Try the following syntax:
more /etc/passwd
more /etc/group

Summing up

We explained various Linux and Unix commands that one can use to search for existing users and group in /etc/passwd and /etc/group files, respectively. Make sure you check out the following man pages using the man command:

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Comments on this entry are closed.

don’t forget the “:” after the username otherwise you could end up with this scenario:

$ egrep -i “^vivek” /etc/passwd
vivek:x:1000:1000:Vivek Gite. /home/vivek:/bin/bash
viveks:x:1001:1001:Vivek Smith. /home/viveks:/bin/bash

I really wish the author would update the article to include that because you know 7 years later and still no fix? Worse yet, it’s the first Google search result for “linux check if group exists”.

If you are using NIS do the following:

ypcat passwd | grep vivek

The ‘id’ command should be demonstrated first in this tutorial, as systems using LDAP (other or remote authentication services) will not have users in the local files.

Also why the uses of egrep when a simple grep will do. Keep it simple for the beginners your aiming at.

You should look at getent rather than grepping the local files. “getent passwd” or “getent group” will provide a unified view of users or groups available, respecting your NSS (Name Service Switch) configuration (which is important when you have additional users or groups via LDAP or NIS).

hey Vivek, that was cool..

many of us surely wont care if its grep or egrep ( or fgrep) as long as it does the job and we are taught these wonderful tricks..

Can you please tell me a command to list all of existing user ?

U can try
egrep “*” /etc/passwd
or
egrep “?” /etc/passwd

Very nice site, I could get, what i want in seconds rather than in minutes

`id` comand does not check if groups exist.
`man id`

Print user and group information for the specified USERNAME

the -g flag prints out the primary group id for the user

have you find any solution for that?

Hello
Linux Gurus,
Is there a Command to find out user creation date ?

or any other possible ways to find the same.

please help me
Its urgent.

Thanks In Advance

please tell everyone you ask.
no way to list the user is not disabled in linux.
and has been in how long dis.

The grep approaches are all wrong. You are assuming that an user won’t pick a name that is a started substring of an existing group. Even worse, if you choose to limit the ‘username’ string you could match a group instead of a user. You will mistakenly get output from the script thinking that the user ‘apache’ (or whatever) exists…

You can’t play with strings without semantics. You need a tool that in fact *knows* that what you are talking about is indeed a user.

The best approach for not playing with strings semantics is the id command:

NAME
id – print real and effective user and group IDs

As davidhi mentioned
Using getent is a much better solution in my opinion

# search for user named ‘vivek’
getent passwd vivek

#search for group named ‘vivek’
getent group vivek

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