Running shell command from Gradle script

Question

I am having the darndest time trying to figure out how to run a shell command from Gradle, since it seems like Gradle makes it very difficult to do this.

Here is the command:

git branch --merged | grep -v \* | grep -v master | grep -v develop | grep -v dmz | xargs git branch -D

It's just a convenience command to clean up local branches that have been merged.

Here is the task I created:

task gitCleanLocalBranches {
    doLast {
        exec {
            workingDir '.'
            commandLine 'git branch --merged | grep -v \\* | grep -v master | grep -v develop | grep -v dmz | xargs git branch -D'

        }
    }
}

The task fails with:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':gitCleanLocalBranches'.
> A problem occurred starting process 'command 'git branch -a''

* Try:
Run with --info or --debug option to get more log output.

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':gitCleanLocalBranches'.
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100)
        ...
Caused by: org.gradle.process.internal.ExecException: A problem occurred starting process 'command 'git branch --merged | grep -v \* | grep -v master | grep -v develop | grep -v dmz | xargs git branch -D''
        at org.gradle.process.internal.DefaultExecHandle.execExceptionFor(DefaultExecHandle.java:222)
        ... 3 more
Caused by: net.rubygrapefruit.platform.NativeException: Could not start 'git branch --merged | grep -v \* | grep -v master | grep -v develop | grep -v dmz | xargs git branch -D'
        at net.rubygrapefruit.platform.internal.DefaultProcessLauncher.start(DefaultProcessLauncher.java:27)
        ... 4 more
Caused by: java.io.IOException: Cannot run program "git branch --merged | grep -v \* | grep -v master | grep -v develop | grep -v dmz | xargs git branch -D" (in directory "/home/wlaw/sterlib"): error=2, No such file or directory
        at net.rubygrapefruit.platform.internal.DefaultProcessLauncher.start(DefaultProcessLauncher.java:25)
        ... 6 more
Caused by: java.io.IOException: error=2, No such file or directory
        ... 7 more

So I figured that the command is too complicated so I tried something simpler, and changed commandLine to:

commandLine 'git branch -a'

But I got the exact same error. Why is Gradle not able to find anything in the PATH environment variable?

Answer 1

The command to execute and its arguments must be separate parameters to pass to commandLine, like this:

commandLine 'git', 'branch', '-a'

If you want to execute a complicated pipeline as in your first example, you can wrap it in a shell script.

I cannot test this, but I think this should work as well:

commandLine 'sh', '-c', 'git branch --merged | grep -v -e \* -e master -e develop -e dmz | xargs git branch -D'

Note: I took the liberty and simplified the grep a bit.

Lastly, you could also create a Git alias in your .gitconfig to wrap the complex pipeline.

Answer 2

If you need to save the command output you could do this:

def gitBranchA = "git branch -a".execute().text.trim()