Processes

The Linux kernel is the core of a Linux installation. The kernel manages memory, provides software with a way to access the hard disk, doles out CPU time, and performs other critical low-level tasks. The kernel is loaded early in the boot process, and it’s the kernel that’s responsible for managing every other piece of software on a running Linux computer.


More about processes

Normally at boot, one process is started /sbin/init. Then everything else is managed by init and are called child processes. (sometimes also referred to as daemons)

Internally, the kernel maintains process information in the process table . Tools such as ps and top (described shortly) enable you to view and manipulate this table.


Process ID numbers

Every process has a PID. Init’s id is normally 1. Each process also has a parent process id(PPID).


More on Processes


More on Processes

Nice values


More on Nice


More on Nice

Examples:


Process related commands


Process states

code state
D uninterruptable sleep (I/O is happening)
R running
S interruptable sleep (waiting for event to complete)
T stopped or paused
Z defunct (zombie)

Process Signals

Messages sent between processes. A numeric value.

Names:


Process related files