The document details a GLC Networks webinar on managing processes in Unix/Linux, led by trainer Achmad Mardiansyah. It includes an overview of Unix processes, process management, signals, and practical exercises, alongside the organization's background and training offerings. The session encourages participant interaction and feedback, aiming to share knowledge and experiences in the field of networking and IT.

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Managing
Process in
UNIX/Linux
GLC webinar, 24 Dec 2020
Achmad Mardiansyah
achmad@glcnetworks.com
GLC Networks, Indonesia
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Agenda
● Introduction
● UNIX process
● Process management
● Background vs foreground process
● Signal
● Live practice
● Q & A
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introduction
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What is GLC?
● Garda Lintas Cakrawala (www.glcnetworks.com)
● Based in Bandung, Indonesia
● Areas: Training, IT Consulting
● Certified partner for: Mikrotik, Ubiquity, Linux foundation
● Product: GLC radius manager
● Regular event
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Trainer Introduction
● Name: Achmad Mardiansyah
● Base: bandung, Indonesia
● Linux user since 1999, mikrotik user since 2007, UBNT
2011
● Mikrotik Certified Trainer
(MTCNA/RE/WE/UME/INE/TCE/IPv6)
● Mikrotik/Linux Certified Consultant
● Website contributor: achmadjournal.com, mikrotik.tips,
asysadmin.tips
● More info:
http://au.linkedin.com/in/achmadmardiansyah
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Past experiences
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● 2020 (Congo DRC, Malaysia): IOT integration,
network automation
● 2019, Congo (DRC): build a wireless ISP from
ground-up
● 2018, Malaysia: network revamp, develop billing
solution and integration, setup dynamic routing
● 2017, Libya (north africa): remote wireless migration
for a new Wireless ISP
● 2016, United Kingdom: workshop for wireless ISP,
migrating a bridged to routed network
● 2015, West Kalimantan: supporting wireless
infrastructure project

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About GLC webinar?
● First webinar: january 1, 2010 (title:
tahun baru bersama solaris - new year
with solaris OS)
● As a sharing event with various topics:
linux, networking, wireless, database,
programming, etc
● Regular schedule
● Irregular schedule: as needed
● Checking schedule:
http://www.glcnetworks.com/schedule
● You are invited to be a presenter
○ No need to be an expert
○ This is a forum for sharing: knowledge,
experiences, information
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Please introduce yourself
● Your name
● Your company/university?
● Your networking experience?
● Your mikrotik experience?
● Your expectation from this course?
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UNIX process
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What is process
Process is an instance (execution) of a program.
Properties:
● OS will allocate resource to process (CPU, RAM)
● Have a process id
● Can have child process
Example:
● Executing command
● Running a GUI
● Open a browser, accessing URL
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Process type
● Foreground
○ Default mode when executing process
○ Will occupy console, cannot do anything else
● Background
○ Usually for daemon/services
○ Can be done using “&” during execution
Multitasking?
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Zombie and orphan process
● In normal situation:
○ when a child process is killed, the parent process is updated via a SIGCHLD signal. Then the
parent can do some other task or restart a new child as needed.
● In not normal situation:
○ parent process is killed before its child is killed.
○ the "parent of all processes," the init process, becomes the new PPID (parent process ID). In
some cases, these processes are called orphan processes.
● Zombie process (Z)
○ This is a zombie or defunct process
○ The process is dead and not being used
● Orphan processes.
○ They have completed execution but still find an entry in the process table.
●
●
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Process vs job
● Process
○
● Job:
○
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Process vs thread
● Process
○ Normal procss
● Thread
○ Aka LWP (lightweight process)
○ One process that is divided into several subprocess (aka. thread).
○ The subprocess is not called child process
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Process management
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Managing process
● Display process:
○ ps
○ Top
● job
● Send signal:
○ kill
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Sending signal to process
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What, why is signal?
● Signals are a limited form of inter-process communication (IPC)
● To send data/command between process
● Typically used in Unix, Unix-like, and other POSIX-compliant operating
systems.
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Example of signal
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Signal Portable
number
Default action Description
SIGABRT 6 Terminate (core dump) Process abort signal
SIGALRM 14 Terminate Alarm clock
SIGBUS N/A Terminate (core dump) Access to an undefined portion of a memory object
SIGCHLD N/A Ignore Child process terminated, stopped, or continued
SIGCONT N/A Continue Continue executing, if stopped
SIGFPE 8 Terminate (core dump) Erroneous arithmetic operation
SIGHUP 1 Terminate Hangup
SIGILL 4 Terminate (core dump) Illegal instruction
SIGINT 2 Terminate Terminal interrupt signal

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LIVE practice
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preparation
● SSH client
● SSH parameters
○ SSH address
○ SSH port
○ SSH username
○ SSH password
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R1
AS11
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SW86
192.168.86.X/24
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TOPOLOGY 1
LAB: Mikrotik
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Q & A
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Interested? Just come to our training...
● Topics are arranged in systematic and logical way
● You will learn from experienced teacher
● Not only learn the materials, but also sharing experiences, best-practices, and
networking
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End of slides
● Thank you for your attention
● Please submit your feedback: http://bit.ly/glcfeedback
● Like our facebook page: https://www.facebook.com/glcnetworks
● Slide: http://www.slideshare.net/r41nbuw
● Recording (youtube): https://goo.gl/28ABHU
● Stay tune with our schedule
● Any questions?
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