The Android Debug Bridge is a very usefull tool to test Android apps.
List the devices available (e.g. connected via USB cable)
$ $ANDROID_HOME/platform-tools/adb devices
List of devices attached
ABCG425PCL device
Install a freshly created Android debug app:
$ $ANDROID_HOME/platform-tools/adb install /tmp/android-debug.apk
[100%] /data/local/tmp/android-debug.apk
pkg: /data/local/tmp/android-debug.apk
Failure [INSTALL_FAILED_UPDATE_INCOMPATIBLE]
Ooops. Seems I created the same app with two different keys...
Find the duplicate app:
$ $ANDROID_HOME/platform-tools/adb shell 'pm list packages -f' | grep foo.bar
package:/data/app/foo.bar/base.apk=foo.bar
Remove the old version of the Android app from the device:
$ $ANDROID_HOME/platform-tools/adb uninstall foo.bar
Succes
Those are my favorite basic adb commands. Have fun!