---
title: who — Show logged-in users
date: 2026-10-20
time: 12:00
model: admin
category: programs
author_type: human
summary: Lists users currently logged in, with terminal, login time and source address.
tags: program, server log recording and analysis, who
---

Lists users currently logged in, with terminal, login time and source address.

## Basic Information

| Command Name | who |
| --- | --- |
| One-line Introduction | Lists users currently logged in, with terminal, login time and source address. |
| Provided by | GNU coreutils |
| Official Documentation | https://man7.org/linux/man-pages/man1/who.1.html |
| Supported Operating Systems | Linux, macOS, BSD, WSL |
| Installation Status | Installed by default |
| Category | Linux logs (tags: Log inspection and analysis (tags: who, login, session, utmp)) |

## What is this command?

who prints the current login sessions: user name, terminal, login time and, for remote sessions, the source address.

The data comes from /var/run/utmp, updated on login and logout. It shows only active sessions; use last for historical records.

## What problems does it solve?

- Checking who is connected right now
- Inspecting source addresses for suspicious logins
- Finding which TTY a session uses
- Identifying concurrent operators before maintenance
## Key features

### Session list

The default run shows users, TTYs and times.

- **When to use**: Getting a quick view of sessions
- **What you get**: You immediately see who is connected from where.
- **Limitations**: It can look empty in containers without utmp.
### Boot time

The -b option prints the last boot time.

- **When to use**: Confirming whether the host rebooted
- **What you get**: Gives a quick sense of uptime.
- **Limitations**: Times may be UTC, so check the time zone.
### Concise output

-q or -H prints only names, or output with headers.

- **When to use**: Scripts that only need names
- **What you get**: Parsing becomes simpler.
- **Limitations**: Names with spaces make parsing ambiguous.
## Installation and usage

### Check whether it is installed

```
who --version
```

sudo apt install coreutils   # Debian/Ubuntu
sudo dnf install coreutils   # Fedora

## Real-world examples

### Basic check

Show current login sessions.

```
who
```

### Name-only list

Print only user names.

```
who -q
```

### Last boot time

Check when the host last booted.

```
who -b
```

---
Source (HTML): https://games.aidebatehub.com/programs/linux/logs/who.html
This file is an auto-generated Markdown twin of the DevHub document.