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//
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[[command_line_interface]]
== Command-Line Interface

[.lead]
The command-line interface is one of the primary methods of interacting with Gradle. The following serves as a reference of executing and customizing Gradle use of a command-line or when writing scripts or configuring continuous integration.

Use of the <<gradle_wrapper, Gradle Wrapper>> is highly encouraged. You should substitute `./gradlew` or `gradlew.bat` for `gradle` in all following examples when using the Wrapper.

Executing Gradle on the command-line conforms to the following structure. Options are allowed before and after task names.
----
gradle [taskName...] [--option-name...]
----

If multiple tasks are specified, they should be separated with a space.

Options that accept values can be specified with or without `=` between the option and argument; however, use of `=` is recommended.
----
--console=plain
----

Options that enable behavior have long-form options with inverses specified with `--no-`. The following are opposites.
----
--build-cache
--no-build-cache
----

Many long-form options, have short option equivalents. The following are equivalent:
----
--help
-h
----

[NOTE]
====
Many command-line flags can be specified in `gradle.properties` to avoid needing to be typed. See the <<sec:gradle_configuration_properties, configuring build environment guide>> for details.
====

The following sections describe use of the Gradle command-line interface, grouped roughly by user goal. Some plugins also add their own command line options, for example <<test_filtering,`--tests` for Java test filtering>>. For more information on exposing command line options for your own tasks, see <<sec:declaring_and_using_command_line_options>>.

[[sec:command_line_executing_tasks]]
=== Executing tasks

You can run a task and all of its <<sec:task_dependencies,dependencies>>.
----
❯ gradle myTask
----

You can learn about what projects and tasks are available in the <<sec:command_line_project_reporting, project reporting section>>.

==== Executing tasks in multi-project builds
In a <<intro_multi_project_builds, multi-project build>>, subproject tasks can be executed with ":" separating subproject name and task name. The following are equivalent _when run from the root project_.

----
❯ gradle :mySubproject:taskName
❯ gradle mySubproject:taskName
----

You can also run a task for all subprojects using the task name only. For example, this will run the "test" task for all subprojects when invoked from the root project directory.

----
❯ gradle test
----

When invoking Gradle from within a subproject, the project name should be omitted:

----
❯ cd mySubproject
❯ gradle taskName
----

[NOTE]
====
When executing the Gradle Wrapper from subprojects, one must reference `gradlew` relatively. For example: `../gradlew taskName`. The community http://www.gdub.rocks/[gdub project] aims to make this more convenient.
====

==== Executing multiple tasks
You can also specify multiple tasks. For example, the following will execute the `test` and `deploy` tasks in the order that they are listed on the command-line and will also execute the dependencies for each task.

----
❯ gradle test deploy
----

[[sec:excluding_tasks_from_the_command_line]]
==== Excluding tasks from execution
You can exclude a task from being executed using the `-x` or `--exclude-task` command-line option and providing the name of the task to exclude.

++++
<figure>
    <title>Example Task Graph</title>
    <imageobject>
        <imagedata fileref="img/commandLineTutorialTasks.png"/>
    </imageobject>
</figure>
++++

++++
<sample id="excludeTask" dir="userguide/tutorial/excludeTasks" title="Excluding tasks">
    <output args="dist --exclude-task test"/>
</sample>
++++

You can see that the `test` task is not executed, even though it is a dependency of the `dist` task. The `test` task's dependencies such as `compileTest` are not executed either. Those dependencies of `test` that are required by another task, such as `compile`, are still executed.

[[sec:rerun_tasks]]
==== Forcing tasks to execute

You can force Gradle to execute all tasks ignoring <<sec:up_to_date_checks,up-to-date checks>> using the `--rerun-tasks` option:

----
❯ gradle test --rerun-tasks
----

This will force `test` and _all_ task dependencies of `test` to execute. It's a little like running `gradle clean test`, but without the build's generated output being deleted.

[[sec:continue_build_on_failure]]
==== Continuing the build when a failure occurs

By default, Gradle will abort execution and fail the build as soon as any task fails. This allows the build to complete sooner, but hides other failures that would have occurred. In order to discover as many failures as possible in a single build execution, you can use the `--continue` option.

----
❯ gradle test --continue
----

When executed with `--continue`, Gradle will execute _every_ task to be executed where all of the dependencies for that task completed without failure, instead of stopping as soon as the first failure is encountered. Each of the encountered failures will be reported at the end of the build.

If a task fails, any subsequent tasks that were depending on it will not be executed. For example, tests will not run if there is a compilation failure in the code under test; because the test task will depend on the compilation task (either directly or indirectly).

==== Task name abbreviation

When you specify tasks on the command-line, you don’t have to provide the full name of the task. You only need to provide enough of the task name to uniquely identify the task. For example, it's likely `gradle che` is enough for Gradle to identify the `check` task.

You can also abbreviate each word in a camel case task name. For example, you can execute task `compileTest` by running `gradle compTest` or even `gradle cT`.

++++
<sample id="abbreviateCamelCaseTaskName" dir="userguide/tutorial/excludeTasks" title="Abbreviated camel case task name">
    <output args="cT"/>
</sample>
++++

You can also use these abbreviations with the -x command-line option.

=== Common tasks

The following are task conventions applied by built-in and most major Gradle plugins.

==== Computing all outputs

It is common in Gradle builds for the `build` task to designate assembling all outputs and running all checks.

----
❯ gradle build
----

==== Running applications

It is common for applications to be run with the `run` task, which assembles the application and executes some script or binary.

----
❯ gradle run
----

==== Running all checks

It is common for _all_ verification tasks, including tests and linting, to be executed using the `check` task.

----
❯ gradle check
----

==== Cleaning outputs

You can delete the contents of the build directory using the `clean` task, though doing so will cause pre-computed outputs to be lost, causing significant additional build time for the subsequent task execution.

----
❯ gradle clean
----

[[sec:command_line_project_reporting]]
=== Project reporting

Gradle provides several built-in tasks which show particular details of your build. This can be useful for understanding the structure and dependencies of your build, and for debugging problems.

You can get basic help about available reporting options using `gradle help`.

==== Listing projects

Running `gradle projects` gives you a list of the sub-projects of the selected project, displayed in a hierarchy.

----
❯ gradle projects
----

You also get a project report within build scans. Learn more about https://guides.gradle.org/creating-build-scans/[creating build scans].

==== Listing tasks

Running `gradle tasks` gives you a list of the main tasks of the selected project. This report shows the default tasks for the project, if any, and a description for each task.

----
❯ gradle tasks
----

By default, this report shows only those tasks which have been assigned to a task group. You can obtain more information in the task listing using the `--all` option.

----
❯ gradle tasks --all
----

[[sec:show_task_details]]
==== Show task usage details

Running `gradle help --task someTask` gives you detailed information about a specific task.

++++
<sample id="taskHelp" dir="userguide/tutorial/projectReports" title="Obtaining detailed help for tasks">
    <output args="-q help --task libs"/>
</sample>
++++

This information includes the full task path, the task type, possible command line options and the description of the given task.

==== Reporting dependencies

Build scans give a full, visual report of what dependencies exist on which configurations, transitive dependencies, and dependency version selection.

----
❯ gradle myTask --scan
----

This will give you a link to a web-based report, where you can find dependency information like this.

image::img/gradle-core-test-build-scan-dependencies.png[Build Scan dependencies report]

Learn more in <<inspecting_dependencies>>.

==== Listing project dependencies

Running `gradle dependencies` gives you a list of the dependencies of the selected project, broken down by configuration. For each configuration, the direct and transitive dependencies of that configuration are shown in a tree. Below is an example of this report:

----
❯ gradle dependencies
----

Concrete examples of build scripts and output available in the <<inspecting_dependencies>>.

Running `gradle buildEnvironment` visualises the buildscript dependencies of the selected project, similarly to how `gradle dependencies` visualizes the dependencies of the software being built.

----
❯ gradle buildEnvironment
----

Running `gradle dependencyInsight` gives you an insight into a particular dependency (or dependencies) that match specified input.

----
❯ gradle dependencyInsight
----

Since a dependency report can get large, it can be useful to restrict the report to a particular configuration. This is achieved with the optional `--configuration` parameter:

[[sec:listing_properties]]
==== Listing project properties

Running `gradle properties` gives you a list of the properties of the selected project.

++++
<sample id="propertyListReport" dir="userguide/tutorial/projectReports" title="Information about properties">
    <output args="-q api:properties" ignoreExtraLines="true"/>
</sample>
++++

==== Software Model reports

You can get a hierarchical view of elements for <<software_model,software model>> projects using the `model` task:

----
❯ gradle model
----

Learn more about <<model-report,the model report>> in the software model documentation.


[[sec:command_line_completion]]
=== Command-line completion

Gradle provides bash and zsh tab completion support for tasks, options, and Gradle properties through https://github.com/gradle/gradle-completion[gradle-completion], installed separately.

++++
<figure>
    <title>Gradle Completion</title>
    <imageobject>
        <imagedata fileref="img/gradle-completion-4.0.gif"/>
    </imageobject>
</figure>
++++

[[sec:command_line_debugging]]
=== Debugging options

`-?`, `-h`, `--help`::
Shows a help message with all available CLI options.

`-v`, `--version`::
Prints Gradle, Groovy, Ant, JVM, and operating system version information.

`-S`, `--full-stacktrace`::
Print out the full (very verbose) stacktrace for any exceptions. See also <<sec:command_line_logging, logging options>>.

`-s`, `--stacktrace`::
Print out the stacktrace also for user exceptions (e.g. compile error).  See also <<sec:command_line_logging, logging options>>.

`--scan`::
Create a https://gradle.com/build-scans[build scan] with fine-grained information about all aspects of your Gradle build.

`-Dorg.gradle.debug=true`::
Debug Gradle client (non-Daemon) process. Gradle will wait for you to attach a debugger at `localhost:5005` by default.

`-Dorg.gradle.daemon.debug=true`::
Debug <<gradle_daemon, Gradle Daemon>> process.

[[sec:command_line_performance]]
=== Performance options
Try these options when optimizing build performance. Learn more about https://guides.gradle.org/performance/[improving performance of Gradle builds here].

Many of these options can be specified in `gradle.properties` so command-line flags are not necessary. See the <<sec:gradle_configuration_properties, configuring build environment guide>>.

`--build-cache`, `--no-build-cache`::
Toggles the <<build_cache, Gradle build cache>>. Gradle will try to reuse outputs from previous builds. _Default is off_.

`--configure-on-demand`, `--no-configure-on-demand`::
Toggles <<sec:configuration_on_demand, Configure-on-demand>>. Only relevant projects are configured in this build run. _Default is off_.

`--max-workers`::
Sets maximum number of workers that Gradle may use. _Default is number of processors_.

`--parallel`, `--no-parallel`::
Build projects in parallel. For limitations of this option please see <<sec:parallel_execution>>. _Default is off_.

`--profile`::
Generates a high-level performance report in the `$buildDir/reports/profile` directory. `--scan` is preferred.

`--scan`::
Generate a build scan with detailed performance diagnostics.

image:img/gradle-core-test-build-scan-performance.png[Build Scan performance report]

==== Gradle daemon options
You can manage the <<gradle_daemon,Gradle Daemon>> through the following command line options.

`--daemon`, `--no-daemon`::
Use the <<gradle_daemon, Gradle Daemon>> to run the build. Starts the daemon if not running or existing daemon busy. _Default is on_.

`--foreground`::
Starts the Gradle Daemon in a foreground process.

`--status` (Standalone command)::
Run `gradle --status` to list running and recently stopped Gradle daemons. Only displays daemons of the same Gradle version.

`--stop` (Standalone command)::
Run `gradle --stop` to stop all Gradle Daemons of the same version.

`-Dorg.gradle.daemon.idletimeout=(number of milliseconds)`::
Gradle Daemon will stop itself after this number of milliseconds of idle time. _Default is 10800000_ (3 hours).


[[sec:command_line_logging]]
=== Logging options

==== Setting log level
You can customize the verbosity of Gradle logging with the following options, ordered from least verbose to most verbose. Learn more in the <<logging, logging documentation>>.

`-Dorg.gradle.logging.level=(quiet,warn,lifecycle,info,debug)`::
Set logging level via Gradle properties.

`-q`, `--quiet`::
Log errors only.

`-w`, `--warn`::
Set log level to warn.

`-i`, `--info`::
Set log level to info.

`-d`, `--debug`::
Log in debug mode (includes normal stacktrace).

Lifecycle is the default log level.

[[sec:command_line_customizing_log_format]]
==== Customizing log format
You can control the use of rich output (colors and font variants) by specifying the "console" mode in the following ways:

`-Dorg.gradle.console=(auto,plain,rich,verbose)`::
Specify console mode via Gradle properties. Different modes described immediately below.

`--console=(auto,plain,rich,verbose)`::
Specifies which type of console output to generate.
+
Set to `plain` to generate plain text only. This option disables all color and other rich output in the console output. This is the default when Gradle is _not_ attached to a terminal.
+
Set to `auto` (the default) to enable color and other rich output in the console output when the build process is attached to a console, or to generate plain text only when not attached to a console. _This is the default when Gradle is attached to a terminal._
+
Set to `rich` to enable color and other rich output in the console output, regardless of whether the build process is not attached to a console. When not attached to a console, the build output will use ANSI control characters to generate the rich output.
+
Set to `verbose` to enable color and other rich output like the `rich`, but output task names and outcomes at the lifecycle log level, as is done by default in Gradle 3.5 and earlier.

[[sec:command_line_warnings]]
==== Showing or hiding warnings
By default, Gradle won't display all warnings (e.g. deprecation warnings). Instead, Gradle will collect them and render a summary at the end of the build like:

----
Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0.
----

You can control the verbosity of warnings on the console with the following options:

`-Dorg.gradle.warning.mode=(all,none,summary)`::
Specify warning mode via <<sec:gradle_properties, Gradle properties>>. Different modes described immediately below.

`--warning-mode=(all,none,summary)`::
Specifies how to log warnings. Default is `summary`.
+
Set to `all` to log all warnings.
+
Set to `summary` to suppress all warnings and log a summary at the end of the build.
+
Set to `none` to suppress all warnings, including the summary at the end of the build.

==== Rich Console
Gradle's rich console displays extra information while builds are running.

image::img/rich-cli.png[alt="Gradle Rich Console"]

Features:

 * Logs above grouped by task that generated them
 * Progress bar and timer visually describe overall status
 * Parallel work-in-progress lines below describe what is happening now

[[sec:command_line_execution_options]]
=== Execution options
The following options affect how builds are executed, by changing what is built or how dependencies are resolved.

`--include-build`::
Run the build as a composite, including the specified build. See <<composite_builds, Composite Builds>>.

`--offline`::
Specifies that the build should operate without accessing network resources. Learn more about <<sec:controlling_dependency_caching_command_line,options to override dependency caching>>.

`--refresh-dependencies`::
Refresh the state of dependencies. Learn more about how to use this in the <<sec:controlling_dependency_caching_command_line,dependency management docs>>.

`--dry-run`::
Run Gradle with all task actions disabled. Use this to show which task would have executed.

=== Environment options
You can customize many aspects about where build scripts, settings, caches, and so on through the options below. Learn more about customizing your <<build_environment, build environment>>.

`-b`, `--build-file`::
Specifies the build file. For example: `gradle --build-file=foo.gradle`. The default is `build.gradle`, then `build.gradle.kts`, then `myProjectName.gradle`.

`-c`, `--settings-file`::
Specifies the settings file. For example: `gradle --settings-file=somewhere/else/settings.gradle`

`-g`, `--gradle-user-home`::
Specifies the Gradle user home directory. The default is the `.gradle` directory in the user's home directory.

`-p`, `--project-dir`::
Specifies the start directory for Gradle. Defaults to current directory.

`--project-cache-dir`::
Specifies the project-specific cache directory. Default value is `.gradle` in the root project directory.

`-u`, `--no-search-upward` (deprecated)::
Don't search in parent directories for a `settings.gradle` file.

`-D`, `--system-prop`::
Sets a system property of the JVM, for example `-Dmyprop=myvalue`. See <<sec:gradle_system_properties>>.

`-I`, `--init-script`::
Specifies an initialization script. See <<init_scripts>>.

`-P`, `--project-prop`::
Sets a project property of the root project, for example `-Pmyprop=myvalue`. See <<sec:project_properties>>.

`-Dorg.gradle.jvmargs`::
Set JVM arguments.

`-Dorg.gradle.java.home`::
Set JDK home dir.

[[sec:command_line_bootstrapping_projects]]
=== Bootstrapping new projects

==== Creating new Gradle builds
Use the built-in `gradle init` task to create a new Gradle builds, with new or existing projects.

----
❯ gradle init
----

Most of the time you'll want to specify a project type. Available types include `basic` (default), `java-library`, `java-application`, and more. See <<build_init_plugin, init plugin documentation>> for details.

----
❯ gradle init --type java-library
----

==== Standardize and provision Gradle
The built-in `gradle wrapper` task generates a script, `gradlew`, that invokes a declared version of Gradle, downloading it beforehand if necessary.

----
❯ gradle wrapper --gradle-version=4.4
----

You can also specify `--distribution-type=(bin|all)`, `--gradle-distribution-url`, `--gradle-distribution-sha256-sum` in addition to `--gradle-version`. Full details on how to use these options are documented in the <<gradle_wrapper,Gradle wrapper section>>.

=== Continuous Build

Continuous Build allows you to automatically re-execute the requested tasks when task inputs change.

For example, you can continuously run the `test` task and all dependent tasks by running:

----
❯ gradle test --continuous
----

Gradle will behave as if you ran `gradle test` after a change to sources or tests that contribute to the requested tasks. This means that unrelated changes (such as changes to build scripts) will not trigger a rebuild. In order to incorporate build logic changes, the continuous build must be restarted manually.

==== Terminating Continuous Build

If Gradle is attached to an interactive input source, such as a terminal, the continuous build can be exited by pressing `CTRL-D` (On Microsoft Windows, it is required to also press `ENTER` or `RETURN` after `CTRL-D`). If Gradle is not attached to an interactive input source (e.g. is running as part of a script), the build process must be terminated (e.g. using the `kill` command or similar). If the build is being executed via the Tooling API, the build can be cancelled using the Tooling API's cancellation mechanism.

[[continuous_build_limitations]]
==== Limitations and quirks

[NOTE]
====
Continuous build is an <<feature_lifecycle,incubating>> feature.
====

There are several issues to be aware with the current implementation of continuous build. These are likely to be addressed in future Gradle releases.

[[sec:build_cycles]]
===== Build cycles

Gradle starts watching for changes just before a task executes. If a task modifies its own inputs while executing, Gradle will detect the change and trigger a new build. If every time the task executes, the inputs are modified again, the build will be triggered again. This isn't unique to continuous build. A task that modifies its own inputs will never be considered up-to-date when run "normally" without continuous build.

If your build enters a build cycle like this, you can track down the task by looking at the list of files reported changed by Gradle. After identifying the file(s) that are changed during each build, you should look for a task that has that file as an input. In some cases, it may be obvious (e.g., a Java file is compiled with `compileJava`). In other cases, you can use `--info` logging to find the task that is out-of-date due to the identified files.

[[sec:continuous_build_limitations_jdk9]]
===== Restrictions with Java 9

Due to class access restrictions related to Java 9, Gradle cannot set some operating system specific options, which means that:

* On macOS, Gradle will poll for file changes every 10 seconds instead of every 2 seconds.
* On Windows, Gradle must use individual file watches (like on Linux/Mac OS), which may cause continuous build to no longer work on very large projects.

[[sec:performance_and_stability]]
===== Performance and stability

The JDK file watching facility relies on inefficient file system polling on macOS (see: https://bugs.openjdk.java.net/browse/JDK-7133447[JDK-7133447]). This can significantly delay notification of changes on large projects with many source files.

Additionally, the watching mechanism may deadlock under _heavy_ load on macOS (see: https://bugs.openjdk.java.net/browse/JDK-8079620[JDK-8079620]). This will manifest as Gradle appearing not to notice file changes. If you suspect this is occurring, exit continuous build and start again.

On Linux, OpenJDK's implementation of the file watch service can sometimes miss file system events (see: https://bugs.openjdk.java.net/browse/JDK-8145981[JDK-8145981]).

[[sec:changes_to_symbolic_links]]
===== Changes to symbolic links

 * Creating or removing symbolic link to files will initiate a build.
 * Modifying the target of a symbolic link will not cause a rebuild.
 * Creating or removing symbolic links to directories will not cause rebuilds.
 * Creating new files in the target directory of a symbolic link will not cause a rebuild.
 * Deleting the target directory will not cause a rebuild.

[[sec:changes_to_build_logic_are_not_considered]]
===== Changes to build logic are not considered

The current implementation does not recalculate the build model on subsequent builds. This means that changes to task configuration, or any other change to the build model, are effectively ignored.
