Webinar topic: Managing Process in UNIX/Linux Presenter: Achmad Mardiansyah In this webinar series, We are discussing Managing Process in UNIX/Linux Please share your feedback or webinar ideas here: http://bit.ly/glcfeedback Check our schedule for future events: https://www.glcnetworks.com/schedule/ Follow our social media for updates: Facebook, Instagram, YouTube Channel, and telegram Presentation slide https://youtu.be/F2P3trRPZYo

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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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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
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● Slide: http://www.slideshare.net/r41nbuw
● Recording (youtube): https://goo.gl/28ABHU
● Stay tune with our schedule
● Any questions?
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