How To Manage Process | Use Of Top Command | Monitoring & Troubleshooting Of Linux Server/System
What is Process in linux
A program/command when executed, a special instance is provided by the system to the process. This instance consists of all the services/resources that may be utilized by the process under execution.
Whenever a command is issued in Unix/Linux, it creates/starts a new process. For example, pwd when issued which is used to list the current directory location the user is in, a process starts.
Through a 5 digit ID number Unix/Linux keeps an account of the processes, this number is call process ID or PID. Each process in the system has a unique PID.
Used up pid’s can be used in again for a newer process since all the possible combinations are used.
At any point of time, no two processes with the same pid exist in the system because it is the pid that Unix uses to track each process.
What is top command
The top (table of processes) command shows a real-time view of running processes in Linux and displays kernel-managed tasks. The command also provides a system information summary that shows resource utilization, including CPU and memory usage.
Sort Processes
By default, top sorts the process list using the %CPU column. To sort processes using a different column, press one of the following keys:
M. Sort by the %MEM column.
N. Sort by PID column.
T. Sort by the TIME+ column.
P. Sort by the %CPU column.