nginx-1.15.2.sh

vercomp () {
    if [[ $1 == $2 ]]; then return 0; fi
    local IFS=.
    local i ver1=($2) ver2=($1)
    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
    do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++))
    do
        if [[ -z ${ver2[i]} ]]
        then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]}))
        then
            return 1
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]}))
        then
            return 2
        fi
    done
    return 3
}
getNginxVersion() {
    nginx -v 2>&1 | grep -o -P 'nginx/\K([0-9]+\.[0-9]+\.[0-9]+)'
}
if vercomp 1.15.2 `getNginxVersion`;then
    echo -e "\033[33m"'Eligible. Your nginx version equals 1.15.2'"\033[m"
elif [[ $? -lt 2 ]];then
    echo -e "\033[33m"'Eligible. Your nginx version greather than 1.15.2'"\033[m"
else
    echo -e "\e[91m"'Not Eligible. Your nginx version lower than 1.15.2 or not found.'"\e[39m" >&2
fi