作者在引入conf/global 文件時，就已經對操作系統的類型進行判斷，同時也對DISTRO進行了賦值。
部分代碼，如圖：
顯然文件里的KERNEL_NAME的值就是判斷完成的操作系統，具體分析該值是如何得到的。
就是通過命令“uname –s | tr ‘[a-z]’ ‘[A-Z]’得到的，不過作者在此處把小寫換成了大寫。 接下來分析根據不同操作系統，怎么獲得不同的DISTRO值，代碼如下：
if [ X"${KERNEL_NAME}" == X'linux' ]; then # Directory of RC scripts. export DIR_RC_SCRIPTS='/etc/init.d' if [ -f /etc/redhat-release ]; then # RHEL/CentOS export DISTRO='RHEL' # Get distribution version if grep '/ 6' /etc/redhat-release &>/dev/null; then # version 6.x export DISTRO_VERSION='6' elif grep '/ 7' /etc/redhat-release &>/dev/null; then # version 7.x export DISTRO_VERSION='7' else export UNSUPPORTED_RELEASE='YES' fi # Get distribution name as DISTRO_CODENAME if grep '^Red' /etc/redhat-release &>/dev/null; then # RHEL export DISTRO_CODENAME='rhel' elif grep '^CentOS' /etc/redhat-release &>/dev/null; then # CentOS export DISTRO_CODENAME='centos' elif grep '^Scientific' /etc/redhat-release &>/dev/null; then # Scientific Linux export DISTRO_CODENAME='scientific' else export UNSUPPORTED_RELEASE='YES' fi elif [ -f /etc/lsb-release ]; then # Ubuntu export DISTRO='UBUNTU' # Ubuntu version number and code name: # - 14.04: trusty # - 15.04: vivid export DISTRO_ID="$(grep 'DISTRIB_ID' /etc/lsb-release | awk -F'=' '{PRint $2}')" export DISTRO_VERSION="$(grep 'DISTRIB_RELEASE' /etc/lsb-release | awk -F'=' '{print $2}')" export DISTRO_CODENAME="$(grep 'DISTRIB_CODENAME' /etc/lsb-release | awk -F'=' '{print $2}')" # Unsupported releases: 12.x, 13.x, 14.10 if echo "${DISTRO_VERSION}" | grep -E '^(12|13|14/.10)' &>/dev/null ; then export UNSUPPORTED_RELEASE='YES' fi elif [ -f /etc/debian_version ]; then # Debian export DISTRO='DEBIAN' # Get major release version number export DISTRO_VERSION="$(cat /etc/debian_version)" # Set distro code name and unsupported releases. if grep '^7' /etc/debian_version &>/dev/null || / grep -i '^wheezy' /etc/debian_version &>/dev/null; then export DISTRO_VERSION='7' export DISTRO_CODENAME='wheezy' elif grep '^8' /etc/debian_version &>/dev/null || / grep -i '^jessie' /etc/debian_version &>/dev/null; then export DISTRO_VERSION='8' export DISTRO_CODENAME='jessie' else export UNSUPPORTED_RELEASE='YES' fi # Override settings. export SHELL_NOLOGIN='/usr/sbin/nologin' else export UNSUPPORTED_RELEASE='YES' fielif [ X"${KERNEL_NAME}" == X'FREEBSD' ]; then export DISTRO='FREEBSD' export DISTRO_VERSION="$(uname -r |awk -F'[.-]' '{print $1}')" # Directory of RC scripts. export DIR_RC_SCRIPTS='/usr/local/etc/rc.d' export PYTHON_BIN='/usr/local/bin/python' # Unsupported releases: 7, 8. if echo "${DISTRO_VERSION}" | grep '^[78]' &>/dev/null ; then export UNSUPPORTED_RELEASE='YES' fi export SHELL_BASH='/usr/local/bin/bash' # Default passWord scheme. export DEFAULT_PASSWORD_SCHEME='BCRYPT'elif [ X"${KERNEL_NAME}" == X'OPENBSD' ]; then export DISTRO='OPENBSD' export DISTRO_VERSION="$(uname -r)" # Directory of RC scripts. export DIR_RC_SCRIPTS='/etc/rc.d' export RC_CONF_LOCAL='/etc/rc.conf.local' export SHELL_BASH='/usr/local/bin/bash' export PYTHON_BIN='/usr/local/bin/python' # Unsupported release: 5.6 and earlier versions. if echo "${DISTRO_VERSION}" | grep '^5.[123456]' &>/dev/null ; then export UNSUPPORTED_RELEASE='YES' fi # Default password scheme. export DEFAULT_PASSWORD_SCHEME='BCRYPT'else # Not support *BSD and other distrobutions yet. echo "Error: Your OS is not supported yet." exit 255fi
代碼比較長，不過脈絡比較清晰，首先根據KERNEL_NAME的值判斷是哪種操作系統，作者給出的判斷是3種，分別是LINUX OPENBSD FREEBSD , 也就是該腳本只能在這3種平臺上進行部署，如果需要自己擴展的話，就可以在增加新的判斷，最后如果3種都不是的話，就直接返回255，如下代碼:
echo "Error: Your OS is not supported yet."exit 255
接下來分析當KERNEL_NAME的值為LINUX，腳本做了什么，首先定義了一個變量
export DIR_RC_SCRIPTS='/etc/init.d'
linux中一般啟動腳本都是放在這個目錄里的,LINUX本身也有很多版本，因此作者在此處又進行多種類型的判斷，判斷的依據文件分別是/etc/redhat-release /etc/lsb-release /etc/debian_version這3種文件分別對應rhel/centos ubuntu debian , 從而也說明在LINUX的版本中，只支持這3種，其他的LINUX版本是不支持的，最后作者返回一句代碼：
定義了一個UNSUPPORTED_RELEASE變量，在后續的代碼應該會調用這個變量來判斷是否支持。
針對這3種LINUX，作者又具體細分到不同的小版本中，首先看rhel/centos 系列，下面代碼：
首先根據存在redhat-release文件，定義了DISTRO的值
if [ -f /etc/redhat-release ]; then
export DISTRO='RHEL'
這樣在get_all.sh的腳本里調用時就有了判斷依據，接著判斷具體的版本，
if grep '/ 6' /etc/redhat-release &>/dev/null; then # version 6.x export DISTRO_VERSION='6' elif grep '/ 7' /etc/redhat-release &>/dev/null; then # version 7.x export DISTRO_VERSION='7' else export UNSUPPORTED_RELEASE='YES' fi
顯然只支持6和7兩個版本，也就是安裝時，如果不是這2個版本的話，就會返回unsupport_release的值為YES了。
rhel還有兩個個反編譯版本即centos ，Scientific Linux, 因此作者又定義了一個變量來區別 DISTRO_CODENAME, 代碼如下:
if grep '^Red' /etc/redhat-release &>/dev/null; then # RHEL export DISTRO_CODENAME='rhel' elif grep '^CentOS' /etc/redhat-release &>/dev/null; then # CentOS export DISTRO_CODENAME='centos' elif grep '^Scientific' /etc/redhat-release &>/dev/null; then # Scientific Linux export DISTRO_CODENAME='scientific' else export UNSUPPORTED_RELEASE='YES' fi
顯然在/etc/redhat-release文件里，不同的發行版本有不同的關鍵字，這樣關于紅帽系的操作系統，作者就已經區分完畢了。
接下來關于ubuntu的判斷就簡單多了，看圖
根據/etc/lsb-release的文件是否存在，賦值DISTRO為UBUNTU，然后判斷具體版本，看代碼
export DISTRO_ID="$(grep 'DISTRIB_ID' /etc/lsb-release | awk -F'=' '{print $2}')" export DISTRO_VERSION="$(grep 'DISTRIB_RELEASE' /etc/lsb-release | awk -F'=' '{print $2}')" export DISTRO_CODENAME="$(grep 'DISTRIB_CODENAME' /etc/lsb-release | awk -F'=' '{print $2}')" # Unsupported releases: 12.x, 13.x, 14.10 if echo "${DISTRO_VERSION}" | grep -E '^(12|13|14/.10)' &>/dev/null ; then export UNSUPPORTED_RELEASE='YES' fi
從程序可以看出UBUNTU的ID , RELEASE , CODENAME的值都在/etc/lsb-release的文件里，用grep 和awk匹配后，賦予不同變量的值。
用grep 篩選出系統版本為12,13,14.10的都為不支持版本，目前支持的版本為14.04,15.04
接下來判斷的就是DEBIAN了，同樣是判斷文件，如圖：
文件存在，則DISTRO的值為DEBIAN，接下來判斷版本號：
# Get major release version number export DISTRO_VERSION="$(cat /etc/debian_version)"
cat /etc/debian_version 一個命令就可以得到具體版本，比rhel更容易判斷
接下來對具體版本進行判斷，見代碼：
# Set distro code name and unsupported releases. if grep '^7' /etc/debian_version &>/dev/null || / grep -i '^wheezy' /etc/debian_version &>/dev/null; then export DISTRO_VERSION='7' export DISTRO_CODENAME='wheezy' elif grep '^8' /etc/debian_version &>/dev/null || / grep -i '^jessie' /etc/debian_version &>/dev/null; then export DISTRO_VERSION='8' export DISTRO_CODENAME='jessie' else export UNSUPPORTED_RELEASE='YES' fi
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