User commands and logs
whoami
For convenience, many distributions and users make the current user part of the command prompt – some for every user, others only for the command prompt. However, on systems without such prompts, remembering which account you are logged into can become confusing, such as when you are using su
to change accounts while administering or configuring. For such systems, the whoami
command (Figure 6) can serve as a general compass. It is used without options – unless you are interested in the version number – and returns only the login name of the current account.
who
The who
command is one of the most important commands for gathering information about users and general system settings (Figure 7).
Unmodified by any options, the who
command lists the users except root who are currently logged in and the date and time they logged in. Users may be listed multiple times if they have one or more virtual terminals open. However, if you add the -q
or --count
option, the same information is displayed in a short format that emphasizes the current number of logins. Different options also give basic system information (see Table 1).
Table 1
System Information from the who Command
Short Option | Long Option | Information |
---|---|---|
|
|
Lists dead processes |
|
|
Displays the last time the system was booted |
|
|
Prints active processes |
|
|
Shows current runlevel |
|
|
Gives the last time the system clock was changed |
id
When you log in to Linux, you establish your real username and groups. However, you also can use commands like sudo
and su
to run as a different or effective user. With the id
command, you can quickly find both real and effective usernames.
The unmodified id
command (Figure 8) gives the real UID for the current account, plus the GIDs for any groups to which the account belongs. However, if you add the -a
option, you get the effective UID. Similarly, the -g
or --group
command displays the real GID, but -G
or --groups
(note the spelling difference) prints all the group IDs. If you do not have multiple logins, you might not notice any difference between the real and effective user.
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.
-
ZorinOS 17.1 Released, Includes Improved Windows App Support
If you need or desire to run Windows applications on Linux, there's one distribution intent on making that easier for you and its new release further improves that feature.
-
Linux Market Share Surpasses 4% for the First Time
Look out Windows and macOS, Linux is on the rise and has even topped ChromeOS to become the fourth most widely used OS around the globe.
-
KDE’s Plasma 6 Officially Available
KDE’s Plasma 6.0 "Megarelease" has happened, and it's brimming with new features, polish, and performance.
-
Latest Version of Tails Unleashed
Tails 6.0 is based on Debian 12 and includes GNOME 43.
-
KDE Announces New Slimbook V with Plenty of Power and KDE’s Plasma 6
If you're a fan of KDE Plasma, you'll be thrilled to hear they've announced a new Slimbook with an AMD CPU and the latest version of KDE Plasma desktop.
-
Monthly Sponsorship Includes Early Access to elementary OS 8
If you want to get a glimpse of what's in the pipeline for elementary OS 8, just set up a monthly sponsorship to help fund its continued existence.
-
DebConf24 to be Held in South Korea
Busan will be the location of the latest DebConf running July 28 through August 4
-
Fedora Unleashes Atomic Desktops
Fedora has combined its solid distribution with rpm-ostree system to make it possible to deliver a new family of Fedora spins, called Fedora Atomic Desktops.
-
Bootloader Vulnerability Affects Nearly All Linux Distributions
The developers of shim have released a version to fix numerous security flaws, including one that could enable remote control execution of malicious code under certain circumstances.