update comment

shadowsocks-libev.sh

@@ -30,6 +30,52 @@ if [[ $EUID -ne 0 ]]; then
 fi
 }
 
+#Check system
+check_sys(){
+    local checkType=$1
+    local value=$2
+
+    local release=''
+    local systemPackage=''
+
+    if [[ -f /etc/redhat-release ]]; then
+        release="centos"
+        systemPackage="yum"
+    elif cat /etc/issue | grep -q -E -i "debian"; then
+        release="debian"
+        systemPackage="apt"
+    elif cat /etc/issue | grep -q -E -i "ubuntu"; then
+        release="ubuntu"
+        systemPackage="apt"
+    elif cat /etc/issue | grep -q -E -i "centos|red hat|redhat"; then
+        release="centos"
+        systemPackage="yum"
+    elif cat /proc/version | grep -q -E -i "debian"; then
+        release="debian"
+        systemPackage="apt"
+    elif cat /proc/version | grep -q -E -i "ubuntu"; then
+        release="ubuntu"
+        systemPackage="apt"
+    elif cat /proc/version | grep -q -E -i "centos|red hat|redhat"; then
+        release="centos"
+        systemPackage="yum"
+    fi
+
+    if [[ ${checkType} == "sysRelease" ]]; then
+        if [ "$value" == "$release" ]; then
+            return 0
+        else
+            return 1
+        fi
+    elif [[ ${checkType} == "packageManager" ]]; then
+        if [ "$value" == "$systemPackage" ]; then
+            return 0
+        else
+            return 1
+        fi
+    fi
+}
+
 # Get version
 getversion(){
     if [[ -s /etc/redhat-release ]];then
@@ -41,14 +87,18 @@ getversion(){
 
 # CentOS version
 centosversion(){
+    if check_sys sysRelease centos; then
         local code=$1
-    local version="`getversion`"
+        local version="$(getversion)"
         local main_ver=${version%%.*}
-    if [ $main_ver == $code ];then
+        if [ "$main_ver" == "$code" ];then
             return 0
         else
             return 1
         fi
+    else
+        return 1
+    fi
 }
 
 # Disable selinux
@@ -68,11 +118,17 @@ get_ip(){
 
 # Pre-installation settings
 pre_install(){
+    # Check OS system
+    if check_sys sysRelease centos; then
         # Not support CentOS 5
         if centosversion 5; then
             echo "Not support CentOS 5, please change to CentOS 6 or 7 and try again."
             exit 1
         fi
+    else
+        echo "Error: Your OS is not supported to run it! Please change OS to CentOS and try again."
+        exit 1
+    fi
     #Set shadowsocks-libev config password
     echo "Please input password for shadowsocks-libev:"
     read -p "(Default password: teddysun.com):" shadowsockspwd