I get a NullPointerException when trying to automatically install the Android SDK. The only other plugin I have added to Jenkins is the Node JS plugin.

[android] No Android SDK found; let's install it automatically...
[android] Going to install required Android SDK components...
[android] Installing the 'platform-tool' SDK component(s)...
$ /Users/Shared/Jenkins/Home/tools/android-sdk/tools/android update sdk -u -a -t platform-tool
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 30: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 33: basename: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 40: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 44: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 48: basename: command not found
$ /Users/Shared/Jenkins/Home/tools/android-sdk/tools/android list sdk --extended
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 30: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 33: basename: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 40: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 44: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 48: basename: command not found
[android] Installing the 'tool,extra-android-m2repository,extra-google-m2repository' SDK component(s)...
$ /Users/Shared/Jenkins/Home/tools/android-sdk/tools/android update sdk -u -a -t tool,extra-android-m2repository,extra-google-m2repository
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 30: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 33: basename: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 40: dirname: command not found
/Users/Shared/Jenkins/Home/tools/android-sdk/tools/android: line 44: dirname: command not found
FATAL: null
java.lang.NullPointerException
at hudson.plugins.android_emulator.util.Utils.getToolCommand(Utils.java:398)
at hudson.plugins.android_emulator.util.Utils.runAndroidTool(Utils.java:449)
at hudson.plugins.android_emulator.util.Utils.runAndroidTool(Utils.java:442)
at hudson.plugins.android_emulator.util.Utils.runAndroidTool(Utils.java:436)
at hudson.plugins.android_emulator.SdkInstaller.isPlatformInstalled(SdkInstaller.java:311)
at hudson.plugins.android_emulator.SdkInstaller.installPlatform(SdkInstaller.java:257)
at hudson.plugins.android_emulator.SdkInstaller.installDependencies(SdkInstaller.java:242)
at hudson.plugins.android_emulator.AndroidEmulator.setUp(AndroidEmulator.java:264)
at hudson.model.Build$BuildExecution.doRun(Build.java:156)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:534)
at hudson.model.Run.execute(Run.java:1741)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:410)
Finished: FAILURE