Setup nginx on centos7

make sure nginx service is up and running

curl http://localhost

should return welcome centos html text

add firewall rule(if firewall is on)

awk is mini language for text processing . could be useful when filtering columns or rows

sample text file

filter row

filter column

the samples text file

linux command with samples


find all log files

count how many log files

grep keyword in file

grep keyword in file and use -n to print line number


Install apache marialDB php


If you have nginx installed. need to stop it first (systemctl stop nginx)



test installation

add line

curl http://localhost/info.php

Install Zabbix

Clone and build modsecurity

Linux file system directory structure

bin : user binary files

boot : include files needed when boot system

dev : devices , appear as files

etc : system wide configuration files . user specific configuration file located in each user/home

home : home folder of each user

lib : system libraries . user specific library…

Process life cycle

fork and exec

Fork : Create a separate duplicated process (child process memory space copied from parent )

Exec : create a process replace current entire process (replace pid)


All process created from parent process except ‘init’

Init process created by os kernel , id= 1 , which is the root process (systemd)

Subprocess.popen and os.fock in python

Virtual Memory

In linux there is mapping between virtual address and physical address to abstract application’s memory usage .

How it works

Each program maintain a mapping . what it brings :

#1 if not enough physical memory .could map to disk

#2 memory “hole” on physical memory . each program could…


Software Developer/Technical Writer&Author/body builder

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store