Parse steamcmd output and extract buildid

buildid for public branch is under
depots.branches.public.buildid

The output from app_info_print is a line-oriented
json-like structure which is easily parsed by bash.

tools/arkmanager

@@ -96,11 +96,35 @@ function getCurrentVersion(){
 
 }
 
+#
+# Parse the buildid from steamcmd
+#
+function parseSteamAppVer(){
+  local sname
+  while read name val; do
+    name="${name#\"}"
+    name="${name%\"}"
+    val="${val#\"}"
+    val="${val%\"}"
+    if [ "$name" = "}" ]; then
+      break
+    elif [ "$name" == "{" ]; then
+      parseSteamAppVer "${1}.${sname}"
+    else
+      if [ "$1" == ".depots.branches.public" -a "$name" == "buildid" ]; then
+        echo "$val"
+        break
+      fi
+      sname="${name}"
+    fi
+  done
+}
+
 #
 # Get the current available server version on steamdb
 #
 function getAvailableVersion(){
-  bnumber=`$steamcmdroot/$steamcmdexec +login anonymous +app_info_print "$appid" +quit | grep -EA 5 "^\s+\"public\"$" | grep -E "^\s+\"buildid\"\s+" | tr '[:blank:]"' ' ' | tr -s ' ' | cut -f3 | sed 's/^ //' | cut -c9-14`
+  bnumber=`$steamcmdroot/$steamcmdexec +login anonymous +app_info_print "$appid" +quit | while read name val; do if [ "${name}" == "{" ]; then parseSteamAppVer; break; fi; done`
   return $bnumber
 }