How to use `who` command?

The who command is used to display information about users who are currently logged into the system. Here are some common usages of the who command:

Basic Usage:
Simply type who in the terminal to see a list of logged-in users:
```
who
```
Detailed Information:
To get more detailed information, you can use the -a option:
```
who -a
```
Show User Login Time:
To display the login time of each user, you can use:
```
who -u
```
Show Users Logged in from a Specific Terminal:
You can specify a terminal to see users logged in from that terminal:
```
who pts/0
```
Combine with Other Commands:
You can also combine who with other commands using pipes. For example, to count the number of logged-in users:
```
who | wc -l
```

These commands will help you effectively use the who command to monitor user logins on your Linux system.