Gradle uses the name build.gradle as the default name for a build file. If we write our build code in a file build.gradle then we don't have to specify the build filename when we run tasks. We can create build files with a different name other than build.gradle. For example we can define our build logic in a file sample.gradle. To run the tasks from this build file we can use the command line option -b or --build-file followed by the file name. But we can also change the project settings and set a new default build file name for our project. With the changed project settings we do not have to use the command line options -b or --build-file.

Suppose we have the following build file with the name sample.gradle:

// File: sample.gradle
task sample(description: 'Sample task') << {
    println 'Sample task'
}

defaultTasks 'sample'

To run the sample task from the command line we can use the command line options -b or --build-file:

$ gradle -b sample.gradle
:sample
Sample task

BUILD SUCCESSFUL

Total time: 3.168 secs
$ gradle --build-file sample.gradle
:sample
Sample task

BUILD SUCCESSFUL

Total time: 2.148 secs
$

To change the default build file name for our project we create a file settings.gradle in our project. Inside the settings.gradle file we can change the property buildFileName for rootProject:

// File: settings.gradle
// Change default build file name for this project.
rootProject.buildFileName = 'sample.gradle'

Now we execute the tasks from sample.gradle without the options -b or --build-file:

$ gradle
:sample
Sample task

BUILD SUCCESSFUL

Total time: 3.312 secs
$

Code written with Gradle 2.1.

Original article