sys command¶

update time¶

sudo ntpd ntp.ubuntu.com
sudo ntpdate ntp.ubuntu.com

RAM¶

free
free -m[-g]
cat /proc/meminfo
top #check memory and CPU usage per process, kill it by Ctrl + c
top -b -n 1 > top.txt
htop #similar to top, more control with color, kill it by Ctrl + c

disk space¶

df -h
df -h /dev/sda

w¶

show who is logged on and what they are doing

w [options] user [...]
-h no header
-x

services started up in runlevel 3¶

ls /etc/rc3.d/S*

folder permission¶

chmod 700 yourDirectory/
ls -a  #show all
ls -1  #one line per file
ls -t  #sort latest changes to top
ls -rt #sort latest to bottom