add a validator script for linux platform

Linux/validator.sh

+#!/bin/sh
+# This script accesses the test sites described in README.
+# This file should be updated according to README file.
+
+base() {
+    # use cnnic.cn so that it matches the address in the cert
+    # served, rather than cnnic.net.cn as presented in README
+    wget -O /dev/null https://www.cnnic.cn/ 2>/dev/null && \
+    wget -O /dev/null https://evdemo.cnnic.cn/ 2>/dev/null && \
+    wget -O /dev/null https://wacc.n.shifen.com/ 2>/dev/null && \
+    wget -O /dev/null https://mail.ztgame.com/ 2>/dev/null && \
+    wget -O /dev/null https://211.146.10.133/ 2>/dev/null
+    RESULT=$?
+    if [ $RESULT -eq 0 ];then
+        echo "Failed test sites for BASE incremental-set"
+    else
+        echo "Passed test sites for BASE incremental-set"
+    fi
+}
+
+extended() {
+    wget -O /dev/null https://cstest.cfca.com.cn/ 2>/dev/null && \
+    wget -O /dev/null https://cs.cfca.com.cn/ 2>/dev/null && \
+    wget -O /dev/null https://www.sheca.com/ 2>/dev/null && \
+    wget -O /dev/null https://ibanks.bankofshanghai.com/ 2>/dev/null
+    RESULT=$?
+    if [ $RESULT -eq 0 ];then
+        echo "Failed test sites for EXTENDED incremental-set"
+    else
+        echo "Passed test sites for EXTENDED incremental-set"
+    fi
+}
+
+all() {
+    wget -O /dev/null https://www.wosign.com/ 2>/dev/null
+    RESULT=$?
+    if [ $RESULT -eq 0 ];then
+        echo "Failed test sites for ALL incremental-set"
+    else
+        echo "Passed test sites for ALL incremental-set"
+    fi
+}
+
+echo "---------------------"
+echo "Beginning tests."
+echo "There are 3 tests (BASE/EXTENDED/ALL), each of which would print a"\
+    " 'Passed test' if passes"
+echo "---------------------"
+base
+extended
+all
+echo "---------------------"
+echo "All tests executed."