Operating System

Generate a Certificate Signing Request(CSR) with OpenSSL / Linux

October 3, 2020October 3, 2020 Timmy Tin Leave a comment

Commands:

openssl genrsa -out ~/domain.com.ssl/domain.com.key 2048

1	openssl genrsa -out ~/domain.com.ssl/domain.com.key 2048

openssl req -new -sha256 -key ~/domain.com.ssl/domain.com.key -out ~/domain.com.ssl/domain.com.csr

1	openssl req -new -sha256 -key ~/domain.com.ssl/domain.com.key -out ~/domain.com.ssl/domain.com.csr

References:

https://support.rackspace.com/how-to/generate-a-csr-with-openssl/

Compile FFmpeg + kxmovie (Xcode 7.3, iOS SDK 9)

October 3, 2020October 3, 2020 Timmy Tin Leave a comment

Preparation

http://www.ffmpeg.org/download.html

https://github.com/yuvi/gas-preprocessor

https://github.com/kewlbear/FFmpeg-iOS-build-script

References

http://al1020119.github.io/blog/2016/01/11/ffmpeg-kxmovies/
http://www.liuxiao.org/2015/08/ios-ffmpeg-%E8%A7%86%E9%A2%91%E8%A7%A3%E7%A0%81%E5%BA%93%E7%9A%84-ios-%E7%89%88%E6%9C%AC%E7%BC%96%E8%AF%91%E5%92%8C-kxmovie-%E6%92%AD%E6%94%BE%E5%99%A8/

How to play flv file or stream in iOS

October 3, 2020October 3, 2020 Timmy Tin Leave a comment

FFmpegPlayer-iOS – A movie player for iOS based on FFmpeg.

https://github.com/kolyvan/kxmovie

(FFmpeg + kxmovie)

http://al1020119.github.io/blog/2016/01/11/ffmpeg-kxmovies/

Convert PDF to Images in Linux via Command Line

October 3, 2020October 3, 2020 Timmy Tin Leave a comment

program to convert PDF files into HTML, XML and PNG images

Installation

Debian User install pdftohtml using following command:

sudo apt-get install poppler-utils

1	sudo apt-get install poppler-utils

Red Hat / Fedora user install pdftohtml using following command:

sudo yum install poppler-utils

1	sudo yum install poppler-utils

More details:

https://manpages.debian.org/testing/poppler-utils/pdftohtml.1.en.html

How to fix yum-config-manager: command not found

October 3, 2020October 3, 2020 Timmy Tin Leave a comment

You need to install yum-utils to use yum-config-manager

yum install yum-utils

1	yum install yum-utils

Unable to start firewalld, Active: failed (Result: timeout)

October 3, 2020October 3, 2020 Timmy Tin Leave a comment

Problem:

Try to start firewalld service via the following command

systemctl start firewalld

1	systemctl start firewalld

but get the following error after few seconds no response:

firewalld.service: Start operation timed out. Terminating. 
firewalld.service: Failed with result 'timeout'. 
systemd: Failed to start firewalld - dynamic firewall daemon.

firewalld.service: Start operation timed out. Terminating.

firewalld.service: Failed with result 'timeout'.

systemd: Failed to start firewalld - dynamic firewall daemon.

Solution:

Execute the following command to restart firewalld service

systemctl stop firewalld;pkill -f firewalld;systemctl start firewalld

1	systemctl stop firewalld;pkill -f firewalld;systemctl start firewalld

How to Install NGINX and PHP 7.3 with PHP-FPM on RHEL/CentOS 7

August 7, 2019November 3, 2020 Timmy Tin Leave a comment

Basic Server Setup

# update system
sudo yum install -y http://rpms.remirepo.net/enterprise/remi-release-7.rpm
sudo yum install -y epel-release yum-utils 
sudo yum update -y

# update system

sudo yum install -y http://rpms.remirepo.net/enterprise/remi-release-7.rpm

sudo yum install -y epel-release yum-utils

sudo yum update -y

# temporary switches off SELinux enforcing 
sudo setenforce 0

1 2	# temporary switches off SELinux enforcing sudo setenforce 0

# setup timezone
sudo rm /etc/localtime
sudo ln -s /usr/share/zoneinfo/Hongkong /etc/localtime

# setup ntp service
sudo yum -y install ntp
sudo ntpdate pool.ntp.org
sudo systemctl enable ntpd
sudo systemctl start ntpd

# setup timezone

sudo rm /etc/localtime

sudo ln -s /usr/share/zoneinfo/Hongkong /etc/localtime

# setup ntp service

sudo yum -y install ntp

sudo ntpdate pool.ntp.org

sudo systemctl enable ntpd

sudo systemctl start ntpd

Setup Default PHP Version

## Install PHP 7.3 
yum --enablerepo=remi-php73 install php php-mbstring php-gd php-bcmath php-tidy php-xml php-xmlrpc php-soap php-mysql php-pdo php-devel

## Install PHP 7.2 
yum --enablerepo=remi-php72 install php php-mbstring php-gd php-bcmath php-tidy php-xml php-xmlrpc php-soap php-mysql php-pdo php-devel

## Install PHP 7.1 
yum --enablerepo=remi-php71 install php php-mbstring php-gd php-bcmath php-tidy php-xml php-xmlrpc php-soap php-mysql php-pdo php-devel

## Install PHP 7.3

yum --enablerepo=remi-php73 install php php-mbstring php-gd php-bcmath php-tidy php-xml php-xmlrpc php-soap php-mysql php-pdo php-devel

## Install PHP 7.2

yum --enablerepo=remi-php72 install php php-mbstring php-gd php-bcmath php-tidy php-xml php-xmlrpc php-soap php-mysql php-pdo php-devel

## Install PHP 7.1

yum --enablerepo=remi-php71 install php php-mbstring php-gd php-bcmath php-tidy php-xml php-xmlrpc php-soap php-mysql php-pdo php-devel

Setup NGINX and PHP-FPM

# install NGINX and PHP with PHP-FPM
sudo yum install -y vim nginx php-fpm
sudo systemctl enable nginx php-fpm
sudo systemctl start nginx php-fpm

# install NGINX and PHP with PHP-FPM

sudo yum install -y vim nginx php-fpm

sudo systemctl enable nginx php-fpm

sudo systemctl start nginx php-fpm

Update Configuration

# update PHP configuration
sudo vi /etc/php.ini
:%s#;date.timezone =#date.timezone = Asia/Hong_Kong#
:%s#expose_php = On#expose_php = Off#
:wq

# update PHP configuration

sudo vi /etc/php.ini

:%s#;date.timezone =#date.timezone = Asia/Hong_Kong#

:%s#expose_php = On#expose_php = Off#

:wq

# update php-fpm configuration
sed -i 's/^user =.*$/user = nginx/g' /etc/php-fpm.d/www.conf
sed -i 's/^group =.*$/group = nginx/g' /etc/php-fpm.d/www.conf
cat /etc/php-fpm.d/www.conf

# update php-fpm configuration

sed -i 's/^user =.*$/user = nginx/g' /etc/php-fpm.d/www.conf

sed -i 's/^group =.*$/group = nginx/g' /etc/php-fpm.d/www.conf

cat /etc/php-fpm.d/www.conf

# update NGINX configuration
sudo cp /etc/nginx/nginx.conf /etc/nginx/nginx.conf.bak
sudo tac /etc/nginx/nginx.conf.bak | awk '!p && /}/{print "\n}\n    include /etc/nginx/vhosts/*.conf;";p=1;next} 1' | tac \
| awk '!p && /server {/{print "    index index.php index.html index.htm;\n";p=1} 1' \
| awk '!p && /root/{print "        root         /var/www/html;";p=1;next} 1' \
| sudo tee /etc/nginx/nginx.conf

# update NGINX configuration

sudo cp /etc/nginx/nginx.conf /etc/nginx/nginx.conf.bak

sudo tac /etc/nginx/nginx.conf.bak | awk '!p && /}/{print "\n}\n include /etc/nginx/vhosts/*.conf;";p=1;next} 1' | tac \

| awk '!p && /server {/{print " index index.php index.html index.htm;\n";p=1} 1' \

| awk '!p && /root/{print " root /var/www/html;";p=1;next} 1' \

| sudo tee /etc/nginx/nginx.conf

# create folders and update permission
sudo mkdir -p /etc/nginx/vhosts/
sudo mkdir -p /var/www/html/
sudo mkdir -p /var/www/vhosts/
sudo chown nginx:nginx /var/www/html/ -R
sudo chown nginx:nginx /var/www/vhosts/ -R

# create folders and update permission

sudo mkdir -p /etc/nginx/vhosts/

sudo mkdir -p /var/www/html/

sudo mkdir -p /var/www/vhosts/

sudo chown nginx:nginx /var/www/html/ -R

sudo chown nginx:nginx /var/www/vhosts/ -R

Create Virtual Hosts

# create dummy virtual host
sudo cat > /etc/nginx/vhosts/example.com.conf <<- "EOF"

# redirect to www
##server {
##    listen       80;
##    server_name  example.com;
##    return       301 http://www.example.com$request_uri;
##}

server {
    listen       80;
    server_name  www.example.com;
    root         /var/www/vhosts/example.com/www;

    location / {
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ .php$ {
        #fastcgi_pass unix:/var/run/php-fpm.sock;
        fastcgi_pass 127.0.0.1:9000;
        fastcgi_index /index.php;
        include /etc/nginx/fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_read_timeout 300;
    }
}

EOF

# create dummy virtual host

sudo cat > /etc/nginx/vhosts/example.com.conf <<- "EOF"

# redirect to www

##server {

## listen 80;

## server_name example.com;

## return 301 http://www.example.com$request_uri;

##}

server {

listen 80;

server_name www.example.com;

root /var/www/vhosts/example.com/www;

location / {

try_files $uri $uri/ /index.php?$args;

}

location ~ .php$ {

#fastcgi_pass unix:/var/run/php-fpm.sock;

fastcgi_pass 127.0.0.1:9000;

fastcgi_index /index.php;

include /etc/nginx/fastcgi_params;

fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

fastcgi_read_timeout 300;

}

EOF

# create ip vhost from dummy virtual host 
cat /etc/nginx/vhosts/example.com.conf | sed '/^#/ d' | sed "s/[www.]*example.com/10.0.6.29/" | sudo tee /etc/nginx/vhosts/10.0.6.29.conf
sudo mkdir -p /var/www/vhosts/10.0.6.29/www/
echo "<?php phpinfo();" | sudo tee /var/www/vhosts/10.0.6.29/www/index.php
sudo nginx -s reload

# create ip vhost from dummy virtual host

cat /etc/nginx/vhosts/example.com.conf | sed '/^#/ d' | sed "s/[www.]*example.com/10.0.6.29/" | sudo tee /etc/nginx/vhosts/10.0.6.29.conf

sudo mkdir -p /var/www/vhosts/10.0.6.29/www/

echo "<?php phpinfo();" | sudo tee /var/www/vhosts/10.0.6.29/www/index.php

sudo nginx -s reload

# create www vhost from dummy virtual host 
cat /etc/nginx/vhosts/example.com.conf | sed "s/example.com/yctin.com/" | sed "s/##//" | sudo tee /etc/nginx/vhosts/yctin.com.conf
sudo mkdir -p /var/www/vhosts/yctin.com/www/
echo "<?php phpinfo();" | sudo tee /var/www/vhosts/yctin.com/www/index.php
sudo nginx -s reload

# create www vhost from dummy virtual host

cat /etc/nginx/vhosts/example.com.conf | sed "s/example.com/yctin.com/" | sed "s/##//" | sudo tee /etc/nginx/vhosts/yctin.com.conf

sudo mkdir -p /var/www/vhosts/yctin.com/www/

echo "<?php phpinfo();" | sudo tee /var/www/vhosts/yctin.com/www/index.php

sudo nginx -s reload

# create subdomain vhost from dummy virtual host 
cat /etc/nginx/vhosts/example.com.conf | sed '/^#/ d' | sed "s/example.com/yctin.com/g" | sed "s/www\./demo\./g" | sed "s/www;/demo;/g" | sudo tee /etc/nginx/vhosts/yctin.com.conf
sudo mkdir -p /var/www/vhosts/yctin.com/demo/
echo "<?php phpinfo();" | sudo tee /var/www/vhosts/yctin.com/demo/index.php
sudo nginx -s reload

# create subdomain vhost from dummy virtual host

sudo mkdir -p /var/www/vhosts/yctin.com/demo/

echo "<?php phpinfo();" | sudo tee /var/www/vhosts/yctin.com/demo/index.php

sudo nginx -s reload

Setup Firewall (Optional)

# setup firewall
sudo yum install firewalld -y
sudo systemctl enable firewalld
sudo systemctl start firewalld
sudo firewall-cmd --add-service=http --permanent
sudo firewall-cmd --add-service=https --permanent
sudo systemctl restart firewalld

# setup firewall

sudo yum install firewalld -y

sudo systemctl enable firewalld

sudo systemctl start firewalld

sudo firewall-cmd --add-service=http --permanent

sudo firewall-cmd --add-service=https --permanent

sudo systemctl restart firewalld

SELinux Settings (Optional for SELinux enabled)

# update selinux policy, required for selinux enabled (p.s. not best practice)
sudo setsebool -P httpd_anon_write 1
sudo chcon -u system_u -t httpd_sys_rw_content_t /var/www/html -R
sudo chcon -u system_u -t httpd_sys_rw_content_t /var/www/vhosts/ -R

# Allow PHP connect network
setsebool -P httpd_can_network_connect 1

# Allow PHP connect remote database
setsebool -P httpd_can_network_connect_db 1

# update selinux policy, required for selinux enabled (p.s. not best practice)

sudo setsebool -P httpd_anon_write 1

sudo chcon -u system_u -t httpd_sys_rw_content_t /var/www/html -R

sudo chcon -u system_u -t httpd_sys_rw_content_t /var/www/vhosts/ -R

# Allow PHP connect network

setsebool -P httpd_can_network_connect 1

# Allow PHP connect remote database

setsebool -P httpd_can_network_connect_db 1

Reboot after Setup

sudo reboot

1	sudo reboot

How to Install MySQL 8.0 on RHEL/CentOS 7

August 7, 2019August 7, 2019 Timmy Tin Leave a comment

Basic Server Setup

# update system
sudo yum install epel-release -y
sudo yum update -y

# update system

sudo yum install epel-release -y

sudo yum update -y

# temporary switches off SELinux enforcing 
sudo setenforce 0

1 2	# temporary switches off SELinux enforcing sudo setenforce 0

# setup timezone
sudo rm /etc/localtime
sudo ln -s /usr/share/zoneinfo/Hongkong /etc/localtime

# setup ntp service
sudo yum -y install ntp
sudo ntpdate pool.ntp.org
sudo systemctl enable ntpd
sudo systemctl start ntpd

# setup timezone

sudo rm /etc/localtime

sudo ln -s /usr/share/zoneinfo/Hongkong /etc/localtime

# setup ntp service

sudo yum -y install ntp

sudo ntpdate pool.ntp.org

sudo systemctl enable ntpd

sudo systemctl start ntpd

Setup MySQL 8.0

# adding the MySQL Yum Repository
sudo rpm -Uvh http://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm

# setup mysql server
sudo yum install mysql-server -y
sudo systemctl enable mysqld
sudo systemctl start mysqld

# adding the MySQL Yum Repository

sudo rpm -Uvh http://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm

# setup mysql server

sudo yum install mysql-server -y

sudo systemctl enable mysqld

sudo systemctl start mysqld

# get temporary root password
sudo cat /var/log/mysqld.log | grep "temporary password"
# 2016-10-22T06:14:44.222048Z 1 [Note] A temporary password is 
# generated for root@localhost: [TEMPORARY ROOT PASSWORD]

# config mysql server
mysql_secure_installation

# Securing the MySQL server deployment.
# Enter password for user root: [TEMPORARY ROOT PASSWORD]
# The existing password for the user account root has expired. Please set a new password.
# New password: [NEW PASSWORD]
# Re-enter new password: [NEW PASSWORD]
# Change the password for root ? : N
# Remove anonymous users? : Y
# Disallow root login remotely? : Y
# Remove test database and access to it? : Y
# Reload privilege tables now? : Y

# get temporary root password

sudo cat /var/log/mysqld.log | grep "temporary password"

# 2016-10-22T06:14:44.222048Z 1 [Note] A temporary password is

# generated for root@localhost: [TEMPORARY ROOT PASSWORD]

# config mysql server

mysql_secure_installation

# Securing the MySQL server deployment.

# Enter password for user root: [TEMPORARY ROOT PASSWORD]

# The existing password for the user account root has expired. Please set a new password.

# New password: [NEW PASSWORD]

# Re-enter new password: [NEW PASSWORD]

# Change the password for root ? : N

# Remove anonymous users? : Y

# Disallow root login remotely? : Y

# Remove test database and access to it? : Y

# Reload privilege tables now? : Y

Setup Firewall (Optional)

# setup firewall
sudo yum install firewalld -y
sudo systemctl enable firewalld
sudo systemctl start firewalld
sudo firewall-cmd --add-service=mysql --permanent

# setup firewall

sudo yum install firewalld -y

sudo systemctl enable firewalld

sudo systemctl start firewalld

sudo firewall-cmd --add-service=mysql --permanent

Reboot after Setup

reboot

reboot

Optional Settings for MySQL 8.0

Disable MySQL Strict Mode

# disable MySQL strict mode
vi /etc/my.cnf
sql-mode=
sudo systemctl restart mysqld

# disable MySQL strict mode

vi /etc/my.cnf

sql-mode=

sudo systemctl restart mysqld

Reference: https://dev.mysql.com/doc/refman/5.7/en/sql-mode.html

Fix MySQL Password Expired

To establish a global policy such that passwords never expire.

Update /etc/my.cnf

[mysqld]
default_password_lifetime=0

1 2	[mysqld] default_password_lifetime=0

Reference: https://dev.mysql.com/doc/refman/8.0/en/password-management.html#password-expiration-policy

How to enlarge CentOS 7 persistent disk size in Google Cloud

March 4, 2019March 4, 2019 Timmy Tin Leave a comment

Update Disk Size

gcloud compute disks resize [disk_name] --size [new_disk_size_in_gb] --zone [zone_name]

1	gcloud compute disks resize [disk_name] --size [new_disk_size_in_gb] --zone [zone_name]

Update Partition Size

yum install -y epel-release
yum install -y cloud-utils-growpart
sudo growpart /dev/sda 1

reboot

yum install -y epel-release

yum install -y cloud-utils-growpart

sudo growpart /dev/sda 1

reboot

Update Volumn Size

sudo resize2fs /dev/sda1

1	sudo resize2fs /dev/sda1

sudo xfs_growfs /dev/sda1

1	sudo xfs_growfs /dev/sda1

References

Auto Launch Chrome in Kiosk Mode/Fullscreen Mode with specified URL on macOS Startup

February 14, 2019February 14, 2019 Timmy Tin 1 Comment

Setup Steps:

Start Automator.app
Select Application
Click Show library in the toolbar (if hidden)
Add Run shell script (from the Actions/Utilities)
Paste the script into the script window
Test run
Save somewhere (for example you can make an Applications folder in your HOME, you will get an your_name.app)
Go to System Preferences -> Accounts -> Login items
Add this app
Try reboot

Kiosk Mode Script

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --kiosk --app=http://example.com

1	/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --kiosk --app=http://example.com

Fullscreen Mode Script

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --start-fullscreen --app=http://example.com

1	/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --start-fullscreen --app=http://example.com