Super: http://www.howtoforge.de/howto/bashbefehle-und-programme-um-traffic-und-auslastung-zu-prufen/
Quelle1)
Ubuntu linux has a rich set of commands for getting system info. One of the useful pieces of information that a system administrator might need is to know what the overall system load on a server is.
There are a couple of ways to get this information, which may or may not be enabled on your system. It’s useful to know more than one way to get the uptime information in case the commands are disabled on your shared hosting server.
The uptime command gives information on system load averages for the past 1, 5, and 15 minutes: Example:
[root@ubuntu geek]# uptime 05:59:07 up 87 days, 13:13, 1 user, load average: 0.00, 0.00, 0.39
The w command shows who is logged on and what they are doing, including system load averages for the past 1, 5, and 15 minutes.
[root@ubuntu geek]# uptime 05:59:56 up 87 days, 13:13, 1 user, load average: 0.00, 0.00, 0.39 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT geek pts/0 192.168.1.115 6:31pm 0.00s 0.62s 0.03s /usr/sbin/sshd
The /proc/loadavg file contains information on the system load. Most likely the uptime/w commands utilize this information. The first 3 values contain system load averages for the past 1, 5, and 15 minutes.
[root@ubuntu geek]# cat /proc/loadavg 0.00 0.00 0.39 1/49 15352
There are probably some more commands, but these are the ones off the top of my head that I know of.
ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed '/^ 0.0 /d'
List processes by % cpu usage