be smarter to find a usable echo command

spectre-meltdown-checker.sh

@@ -97,17 +97,31 @@ global_critical=0
 global_unknown=0
 nrpe_vuln=""
 
+echo_cmd=''
 __echo()
 {
 	opt="$1"
 	shift
 	_msg="$@"
+
+	if [ -z "$echo_cmd" ]; then
+		# find a sane `echo` command
+		# we'll try to avoid using shell builtins that might not take options
+		if which echo >/dev/null 2>&1; then
+			echo_cmd=`which echo`
+		else
+			[ -x /bin/echo        ] && echo_cmd=/bin/echo
+			[ -x /system/bin/echo ] && echo_cmd=/system/bin/echo
+		fi
+		# still empty ? fallback to builtin
+		[ -z "$echo_cmd" ] && echo_cmd=echo
+	fi
+
 	if [ "$opt_no_color" = 1 ] ; then
 		# strip ANSI color codes
-		_msg=$(/bin/echo -e  "$_msg" | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g")
+		_msg=$($echo_cmd -e  "$_msg" | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g")
 	fi
-	# explicitly call /bin/echo to avoid shell builtins that might not take options
+	$echo_cmd $opt -e "$_msg"
-	/bin/echo $opt -e "$_msg"
 }
 
 _echo()