System Info
who
Show who is currently logged into the system.
Synopsis
syntax
who [OPTION]...
Examples
List logged-in users
who
Show last boot time
who -b
Quick list with user count
who -q
All info with headers
who -aH
Common options
| Flag | Description |
|---|---|
| -a | Print all information |
| -b | Time of last system boot |
| -q | Quick — only names and count |
| -H | Print column headers |
About who
The `who` command show who is currently logged into the system. System information commands provide insight into hardware, kernel, memory, disk, and user session details.
These are typically the first tools you reach for when diagnosing system problems, capacity planning, or auditing a server's configuration. They work across most Linux distributions without additional packages.
The command accepts 4 commonly used flags shown above, though the full set of options is available in the man page (`man who`). The 4 examples on this page cover typical real-world usage patterns that you can copy and adapt for your own workflows.
Related commands
More System Info Commands
Other commands in the System Info category