we are actually in andoid/app dir

android/app/build.gradle

@@ -98,8 +98,9 @@ def enableProguardInReleaseBuilds = false
 def getVersionCode = { ->
     new ByteArrayOutputStream().withStream { stdOut ->
         exec {
-            commandLine "sh", "../build_no.sh", "--tag"
+            commandLine "sh", "../../build_no.sh", "--tag"
             standardOutput = stdOut
+            errorOutput = System.err
         }
         return stdOut.toString().toInteger()
     }

build_no.sh

@@ -25,7 +25,7 @@ getNumber () {
 REGEX='^build-[0-9]\+$' 
 
 # make sure we have all the tags
-git fetch --tags
+git fetch --tags --quiet
 
 # check if current commit has a build tag
 BUILD=$(git tag --points-at HEAD | grep -e "$REGEX")