CentOS 6 repo Settings

To fix repo settings in CentOS 6

1. make sure there is no proxy or funny settings in
vi /etc/yum.conf

2. There are a couple of files within /etc/yum.repos.d/. Make sure the url are correct (accessible) and enabled=1
ll /etc/yum.repos.d/

3. Cleanup the repo, list and retest
yum –enablerepo=base clean metadata;
yum repolist all
yum search java-1.8.0-openjdk

RedHat / Centos Firewall

To add an exception to firewall
In RedHat/CentOS 6

iptables --line -vnL
iptables -A INPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.0.0/16 -j ACCEPT
iptables -D INPUT -p tcp -s 192.168.0.0/16 -j ACCEPT
service iptables save

In RedHat/CentOS 7

firewall-cmd --list-all
firewall-cmd --permanent --add-port=80/tcp
firewall-cmd --permanent --zone=public --add-source=192.168.0.0/16
firewall-cmd --permanent --zone=public --remove-source=192.168.0.0/16
firewall-cmd --reload
systemctl disable firewalld

Bash string comparison


#!/bin/bash

function test(){
echo ""
echo "TEST $1"
echo "VAR_1: $VAR_1 VAR_2: $VAR_2 "
if [ "$VAR_1" = "false" ]; then echo " VAR_1 is false"; fi
if [ "$VAR_2" = "false" ]; then echo " VAR_2 is false"; fi
if [ "$VAR_1" = "false" ] || [ "$VAR_2" = "false" ]; then echo " At least one is false"; fi
}
VAR_1='true';
VAR_2='true';
test 1

VAR_1='true';
VAR_2='false';
test 2

VAR_1='false';
VAR_2='false';
test 3

function test2(){
echo ""
echo "TEST $1"
echo "VAR_3: $VAR_3 VAR_4: $VAR_4 "
[ -n "$VAR_3" ] && echo " VAR_3 is not null"
[ -z "$VAR_3" ] && echo " VAR_3 is null"
[ -n "$VAR_4" ] && echo " VAR_4 is not null"
[ -z "$VAR_4" ] && echo " VAR_4 is null"
}

VAR_3=""
VAR_4=""
test2 4

VAR_3="3"
VAR_4=""
test2 5

Result

$ /c/tmp/bashtest.sh

TEST 1
VAR_1: true VAR_2: true

TEST 2
VAR_1: true VAR_2: false
VAR_2 is false
At least one is false

TEST 3
VAR_1: false VAR_2: false
VAR_1 is false
VAR_2 is false
At least one is false

TEST 4
VAR_3: VAR_4:
VAR_3 is null
VAR_4 is null

TEST 5
VAR_3: 3 VAR_4:
VAR_3 is not null
VAR_4 is null

Crontab header


# minute (0-59),
# | hour (0-23),
# | | day of the month (1-31),
# | | | month of the year (1-12),
# | | | | day of the week (0=Sunday 1=Monday 2=Tuesday 3=Wednesday 4=Thursday 5=Friday 6=Saturday).
# | | | | | commands

Simple unit test is bash file

Consider the following 3 files:

1. shellTestFramework.sh


#!/bin/bash
# Copyright (c) Ronald Pringadi

# Before each Test
function setUpTest(){
#"Please overwrite this function on your unit test. Something that need to be done before each test"
return 0;
}

function tearDownTest(){
#"Please overwrite this function on your unit test. Something that need to be done after each test"
return 0;
}

# Helping assertion
function assertEqual(){
if [ "$1" == "$2" ]; then
echo "`caller 0`. PASS"
else
echo "`caller 0`. FAIL. $1!=$2"
fi
}

# Helping assertion
function assertNotEqual(){
if [ "$1" != "$2" ]; then
echo "`caller 0`. PASS"
else
echo "`caller 0`. FAIL. $1==$2"
fi
}

# To run all test.
# Will run 'setUpTest()' before each test.
# Will run 'tearDownTest()' after each test.
function runAllTest(){
array=($(compgen -A function |grep -i test))
for i in "${array[@]}"
do
if [ "$i" != "setUpTest" ] && [ "$i" != "runAllTest" ] && [ "$i" != "tearDownTest" ]; then
echo "`setUpTest`"
echo "`$i`"
echo "`tearDownTest`"
fi
done
}

2. osdetector.sh


#!/bin/bash
# Copyright (c) Ronald Pringadi

# Returns String ("ubuntu", "censtos", "redhat", "unknown")
function detectAnyOS(){
OS="unknown"

DETECT="ubuntu"
if [ `detectSpecificOS "$DETECT"` -eq 1 ] ; then
echo $DETECT
return 0
fi

DETECT="centos"
if [ `detectSpecificOS "$DETECT"` -eq 1 ] ; then
echo $DETECT
return 0
fi

DETECT="Red Hat"
if [ `detectSpecificOS "$DETECT"` -eq 1 ] ; then
echo "redhat"
return 0
fi

DETECT="RHEL"
if [ `detectSpecificOS "$DETECT"` -eq 1 ] ; then
echo "redhat"
return 0
fi
}

# Input String ("ubuntu", "Centos", "RedHat")
# Returns String "1"=found, "0"=not found
function detectSpecificOS(){
DETECT=$1
IS_FOUND=`cat /etc/*-release |grep -i "$DETECT"|wc -l`
if [ $IS_FOUND -gt 0 ]; then
echo "1"
else
echo "0"
fi
}

# Returns String ("6", "5.5", "4")
function detectOSVersion(){
# Works for ubuntu
VERSION=`cat /etc/*-release |grep 'DISTRIB_RELEASE='|grep -o '[0-9|.]\+'|head -1`
if [ "$VERSION" != "" ]; then
echo $VERSION
return 0
fi

# Works for Centos
VERSION=`cat /etc/*-release |grep ' release '|grep -o '[0-9|.]\+'|head -1`
if [ "$VERSION" != "" ]; then
echo $VERSION
return 0
fi

# Final resort
VERSION=`cat /etc/*-release |grep -i 'ubuntu\|red hat\|centos'| grep -o '\ [0-9|.]\+'|head -1`
if [ "$VERSION" != "" ]; then
echo $VERSION
return 0
fi

}

# Returns String ("6", "5", "4")
function detectOSMajorVersion(){
VERSION=`detectOSVersion`
MAJOR_VERSION=`echo "$VERSION" |grep -o '[0-9]\+'|head -1`
echo "$MAJOR_VERSION"
}

# Input String OS ("ubuntu", "Centos", "RedHat")
# Input String OSVersion name
# Returns String "1"=supported, "0"=not supported
function isOSSupported(){
SUPPORTED="0"
OS=`echo "$1"| tr '[:upper:]' '[:lower:]'`
VERSION="$2"
MAJOR_VERSION=`echo "$VERSION" |grep -o '[0-9]\+'|head -1`
if [ "$OS" == "ubuntu" ]; then
if [ "$MAJOR_VERSION" == "12" ] || [ "$MAJOR_VERSION" == "13" ] || [ "$MAJOR_VERSION" == "14" ]; then
SUPPORTED="1"
fi
fi
if [ "$OS" == "red hat" ] || [ "$OS" == "redhat" ] || [ "$OS" == "centos" ]; then
if [ "$MAJOR_VERSION" == "6" ]; then
SUPPORTED="1"
fi
fi
echo $SUPPORTED
}

3. osdetector.test.sh


#!/bin/bash
# Copyright (c) Ronald Pringadi
my_dir="$(dirname "$0")"
source "$my_dir/osdetector.sh"
source "$my_dir/shellTestFramework.sh"

# Before each Test
function setupTest(){
RELEASE_CONTENT="Ubuntu 14.04.3 LTS"
echo "$RELEASE_CONTENT">/etc/test-release
}

function adetectSpecificOSTest(){
DETECT="Ubuntu"
RESULT=`detectSpecificOS $DETECT`
assertEqual "$RESULT" "1"

DETECT="Centos"
RESULT=`detectSpecificOS $DETECT`
assertEqual "$RESULT" "0"
}

function detectAnyOSTest(){
RESULT=`detectAnyOS`
assertEqual "$RESULT" "ubuntu"
assertNotEqual "$RESULT" "centos"
}

function detectOSAndOsVersionTest(){
RELEASE_CONTENT="Ubuntu 14.04.3 LTS"
echo "$RELEASE_CONTENT" > /etc/test-release
RESULT=`detectOSVersion`
assertEqual "$RESULT" "14.04.3"
RESULT=`detectOSMajorVersion`
assertEqual "$RESULT" "14"
RESULT=`detectAnyOS`
assertEqual "$RESULT" "ubuntu"

RELEASE_CONTENT="CentOS release 6.6 (Final)"
echo "$RELEASE_CONTENT" > /etc/test-release
RESULT=`detectOSVersion`
assertEqual "$RESULT" "6.6"
RESULT=`detectOSMajorVersion`
assertEqual "$RESULT" "6"
RESULT=`detectAnyOS`
assertEqual "$RESULT" "centos"

RELEASE_CONTENT="CentOS Linux release 7.1.1503 (Core)"
echo "$RELEASE_CONTENT" > /etc/test-release
RESULT=`detectOSVersion`
assertEqual "$RESULT" "7.1.1503"
RESULT=`detectOSMajorVersion`
assertEqual "$RESULT" "7"
RESULT=`detectAnyOS`
assertEqual "$RESULT" "centos"

RELEASE_CONTENT="Red Hat Enterprise Linux Server release 6.3 (Santiago)"
echo "$RELEASE_CONTENT" > /etc/test-release
echo "$RELEASE_CONTENT" >> /etc/test-release
RESULT=`detectOSVersion`
assertEqual "$RESULT" "6.3"
RESULT=`detectOSMajorVersion`
assertEqual "$RESULT" "6"
RESULT=`detectAnyOS`
assertEqual "$RESULT" "redhat"
}

function isOSSupportedTest(){

RESULT=`isOSSupported "ubuntu" "11"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "ubuntu" "12"`
assertEqual "$RESULT" "1"

RESULT=`isOSSupported "ubuntu" "13"`
assertEqual "$RESULT" "1"

RESULT=`isOSSupported "ubuntu" "14"`
assertEqual "$RESULT" "1"

RESULT=`isOSSupported "ubuntu" "15"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "redhat" "5"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "redhat" "6"`
assertEqual "$RESULT" "1"

RESULT=`isOSSupported "redhat" "7"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "red hat" "5"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "red hat" "6"`
assertEqual "$RESULT" "1"

RESULT=`isOSSupported "red hat" "7"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "centos" "5"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "centos" "6"`
assertEqual "$RESULT" "1"

RESULT=`isOSSupported "centos" "7"`
assertEqual "$RESULT" "0"

RESULT=`isOSSupported "Fedora" "50"`
assertEqual "$RESULT" "0"

}

runAllTest