Page 50 - DCAP106_OPERATING_SYSTEM_TOOLS

Unit 2: Red Hat Linux 9 Basics

Notes
Example: Suppose that you are at the terminal prompt, it means that you are
communicating with the shell interpreter program.
All executing programs are considered as processes that have been launched by some other
parent processes. Thus, we can represent all the running processes in the form of a hierarchical
tree.

Notes When launching a child process, the parent process creates a copy of it by forking,
and then executes the child program in the memory space of the new copy.

2.6.2 Viewing Running Processes

The System Monitor program provides permission to see the processes that are running in the
machine. Figure 2.23 shows the list of processes.

Figure 2.23: List of Processes

The processes sorted by any column on display can be viewed by just clicking at the respective
column header. We have sorted the processes in accordance with their memory usage.

We can utilze the ps program at the terminal in order to view the processes running in the
machine in a non-dynamic manner. We can make use of the ps program without any arguments
to view every process running within your present logging session. In order to view every
process running in the machine, it is required to use the command ps ax:
The pstree program provides permission to view every process in a tree format. Thus, it provides
a good idea of the hierarchical nature of processes. The following displays just a small part of the
output of this program, starting with the init process (Figure 2.24):
The terminal also provides the top program. It provides permission to view the process list in an
interactive way. It displays the process list in a similar manner to the GUI system monitor, and
permits us to arrange the results by clicking on different keystrokes. We can click on the help key
in order to obtain more help on the keys that are used for sorting the display.

LOVELY PROFESSIONAL UNIVERSITY 43