List the users logged in on the machine.
List all users logged in on your network. The rwho service must be enabled for this command to work.
System info about a user. Try: finger root last. This lists the users last logged-in on your system.
Show the last (1000 or so) commands executed from the command line on the current account. The | more causes the display to stop after each screen fill.
history | more
Print working directory, i.e. display the name of your current directory on the screen.
Print the name of the local host (the machine on which you are working).
Print your login name.
Print user id (uid) and his/her group id (gid), effective id (if different from the real id) and the supplementary groups.
Print or change the operating system date and time. E.g., change the date and time to 2000-12-31 23:57 using this command
To set the hardware clock from the system clock, use the command (as root) setclock
Determine the amount of time that it takes for a process to complete+ other info. Don't confuse it with date command. For e.g. we can find out how long it takes to display a directory content using time ls
Amount of time since the last reboot
List the processes that are had been run by the current user.
List all the processes currently running, even those without the controlling terminal, together with the name of the user that owns each process.
ps aux | more
Keep listing the currently running processes, sorted by cpu usage (top users first).
Info on your server.
Memory info (in kilobytes).
Print disk info about all the file systems in a human-readable form.
Print detailed disk usage for each subdirectory starting at root (in a human-readable form).
du / -bh | more
(as root. Use /sbin/lsmod to execute this command when you are a non-root user.) Show the kernel modules currently loaded.
Show the current user environment.
Show the content of the environment variable PATH. This command can be used to show other environment variables as well. Use set to see the full environment.
Print kernel messages (the current content of the so-called kernel ring buffer). Press q to quit less. Use less /var/log/dmesg to see what dmesg dumped into the file right after bootup. - only works on dedicated systems
dmesg | less