Linux Pocket Guide, 2nd Edition

Viewing Processes

ps	List process.
uptime	View the system load.
w	List active processes for all users.
top	Monitor resource-intensive processes interactively.
gnome-system-monitor	Monitor system load and processes graphically.
xload	Simple, graphical monitor of system load.
free	Display free memory.

A process is a unit of work on a Linux system. Each program you run represents one or more processes, and Linux provides commands for viewing and manipulating them. Every process is identified by a numeric process ID, or PID.

Processes are different from jobs (see Shell Job Control): processes are part of the operating system, whereas jobs are higher-level constructs known only to the shell in which they’re running. A running program comprises one or more processes; a job consists of one or more programs executed as a shell command.