Android Studio : install Release App by command line

So there is no such task. You can see all available tasks calling gradlew tasks. To assemble release version of apk call gradlew assembleRelease and then using adb install it.

My experience has been that the installRelease task does not become available until you define the signingConfigs in the buildTypes.release block of your build file, as shown in step 3 of Signing in Release Mode. Without signingConfigs, you will get other release tasks, such as assembleRelease, but not installRelease.