#!/bin/bash
test=' defaultConfig {
    applicationId "com.service_app"
    minSdkVersion rootProject.ext.minSdkVersion
    targetSdkVersion rootProject.ext.targetSdkVersion
    versionCode 1
    versionName "1.0"
}'
echo "Enter versionCode"
read versionCode
echo "$versionCode"
sed "s/\(versionCode[[:space:]]*\)[0-9]*/\\1${versionCode}/" <<< "$test"