last

The last command prints out the last few logins to the system.

$ last
# just take a look

$ last -n 10 cyan
# look at cyan's last 10 logins

The '-n' option tells last how many logins to print out.

On Linux systems the man page gets its information from the wtmp logs, which are moved about monthly. So on the first day of a month, you won't be able to see login information for the previous month. For more information, check out:

# the manual for last
man last

These commands tell you about other users. To interact with other users, you need the write and talk commands.