This tutorial shows you how to list users in Linux. You’ll also learn to list only the logged users.
Today different
Linux on the other hand is very strong on this matter as it allows multiple users to work at the same time on the system in an independent way. It can even allow a single user to open several sessions even from different locations in order to work on the system.
Here are some hints & tricks to handle users in Linux.
List all the users on Linux
Let’s say you want to create a sudo user in Linux. Probably, the very first thing to know is how to know what users are in my system. There are several ways you can obtain the list of users in Linux.
1. Show users in Linux using less /etc/passwd
This command allows sysops to list the the users that are locally stored in the system. It will give the listing in structured way as:
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
johndoe:x:1000:1000:John Doe,,,:/home/helder:/bin/bash
davmail:x:127:65534::/var/lib/davmail:/usr/sbin/nologin
statd:x:128:65534::/var/lib/nfs:/usr/sbin/nologin
/etc/passwd (END)The structure in the above output goes as:
- User name
- Encrypted password (
xrepresentspassword is stored) User ID number (UID)- User’s group ID number (GID)
- Full name
- User’s home directory
- User’s Login shell (default is bash shell)
Why so many users? Which ones
The list shows a lot more users than you expected because it lists all the system users too.
Now if you want to distinguish the normal users from the system users, you can refer to the User identifier (UID) number
You’ll also notice that some of the users have ‘nologin’ at the end of their line. This means that these users cannot login to the system. These users are also referred as psedu-users.
2. View users using getent passwd
This command will give you a similar output as “less /etc/
This conf includes
3. List Linux users with compgen
If you just want to list all the usernames without any additional information, you can use the
compgen -u
The output would be like this:
compgen -u root daemon bin sys sync games man lp mail news uucp proxy www-data backup list irc gnats nobody systemd-network systemd-resolve syslog messagebus _apt uuidd avahi-autoipd usbmux dnsmasq rtkit cups-pk-helper speech-dispatcher whoopsie kernoops saned pulse avahi colord hplip geoclue gnome-initial-setup gdm abhishek
Tip
You can use
A few tips about listing users in Linux
You just saw three ways to view users in Linux. Here are a few tips that would help you while dealing with the users listing.
List only the usernames
You already have the
If we would like to only get a list of the usernames in the system, you can use the awk command or the cut command to filter the output of the other two commands we saw earlier.
cut -d: -f1 /etc/passwd
or
getent passwd | awk -F: '{ print $1}'
Any of these will give us a filtered list of users, showing only the very first column which is username:
root
daemon
bin
sys
sync
games
man
lp
mail
news
johndoe
davmail
statdCheck if a username already exists in the system
This might be useful if you want to know if a particular username already exists in the system:
getent passwd | grep johndoe
johndoe:x:1000:1000:John Doe,,,:/home/johndoe:/bin/bashList all the connected users
If you want to know what users are currently logged into your system, then you need to perform a simple ‘who’ on your command line and this will immediately list current usernames with an active session to your system
user@system:~$ who
johndoe :0 2019-01-28 21:35 (:0)
harrysmith pts/0 2019-02-01 09:51 (192.168.1.1)
stevejones pts/1 2019-02-02 09:51 (192.168.1.173)In this case, the listing will give you not only the list of usernames connected but also how they are connected, since when they are connected and from where they are connected.
The very first column will tell you what username is it.
The second column will give you what type of connection it is: if it’s represented with a “:X” where X is a number, it means it is using a Graphical User Interface (GUI) or Desktop session such as Gnome, XDE, etc; if it says “pts/X” where X is a number, it means it’s a connection made through SSH protocol (command line).
The third column will tell you since when this session has been connected to the server (date and time). The fourth and last column will give you the location from where it’s connected, if remote it will display the IP from where the connection is made if local (like the GUI) it will display “(:X)” where X is the number of the session in this case and will match the number in the second column for that row.
Wrapping up
As you can see, listing users in Linux is not difficult at all. It consists of simple commands which will output all the information for you, whatever you want to do or obtain of that information is something you need to filter depending on what you want to check on the system.
For example, if you want to list users in a group in Linux, you can do that as well. In a related topic, you may also read about changing users in Linux command line.
I hope you liked this tutorial. If you have any questions or suggestions, please let us know in the comments.
