Linux basic command - top and ps command


Yeastar S-Series PBX is based on Asterisk platform and operating on Linux system.

In this article, you will learn how to operate two basic and very usefull commands: top and ps command.

First you will need to login to SSH of S-Series PBX:


The top command

Top command will print system resources usage of PBX and it will keep updating in real-time, top allows you to monitor all system activities: 


In the top interface, you will see 3 lines of system information and a table of running processes.

Line 1: current memory usage of system

  • used memory
  • available memory
  • shared memory
  • buffer memory
  • cached memory

Line 2: current cpu usage of system

  • cpu% used by the user
  • cpu% used by system
  • cpu% used by low priority processes
  • cpu% that is available
  • cpu% used by I/O
  • cpu% used by hardware interrupts
  • cpu% used by software interrupts

Line3: system load average: 

  • system load average over last 1 minutes: 1.08
  • system load average over last 5 minutes: 1.12
  • system load average over last 15 minutes: 1.16

Main table:

  • PID--Process ID
  • PPID--Parent Process ID
  • USER--Owner of process
  • STAT--State of process: R=running state, S=sleep state, W=wait state, D=sleep state(cannot be interrupted), Z=zombie state
  • VSZ--Virtual memory used by process
  • %VSZ--Pecentage of Virtuall memory used by process
  • %CPU--Pecentage of CPU used by process
  • Command--Process command 

The ps command

Ps commad lists all running process up to date


  • PID--Process ID
  • USER--Owner of process
  • TIME--Process running time
  • COMMAND--Process command


In summary, top and ps commands are mostly used when you have system memory or CPU overload issue. Typicall behaviors are WebGUI stuck, bad audio quality, system slow response etc. When you have memory or CPU overload issue, run top and ps command, then post us the result so we can quickly locate and solve the problem.





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